Against age limits for men in reproductive care

Almost all countries and fertility clinics impose age limits on women who want to become pregnant through Assisted Reproductive Technologies (ART). Age limits for aspiring fathers, however, are much less common and remain a topic of debate. This article departs from the principle of reproductive autonomy and a conditional positive right to receive ART, and asks whether there are convincing arguments to also impose age limits on aspiring fathers. After considering three consequentialist approaches to justifying age limits for aspiring fathers, we take in a concrete normative stance by concluding that those are not strong enough to justify such cut-offs. We reinforce our position by drawing a comparison between the case of a 39-year-old woman who wants to become a single mother via a sperm donor on the one hand, and on the other hand the same woman who wants to have a child with a 64-year-old man who she loves and who is willing to care for the child as long as he is able to. We conclude that, as long as appropriate precautions are taken to protect the welfare of the future child, couples who want to receive fertility treatment should never be limited on the basis of the age of the (male) partner. An absence of age limits for men would respect the reproductive autonomy of both the man and the woman.

Paternal aging impacts expression and epigenetic markers as early as the first embryonic tissue lineage differentiation

BACKGROUND

Advanced paternal age (APA) is associated with adverse outcomes to offspring health, including increased risk for neurodevelopmental disorders. The aim of this study was to investigate the methylome and transcriptome of the first two early embryonic tissue lineages, the inner cell mass (ICM) and the trophectoderm (TE), from human blastocysts in association with paternal age and disease risk. High quality human blastocysts were donated with patient consent from donor oocyte IVF cycles from either APA (≥ 50 years) or young fathers. Blastocysts were mechanically separated into ICM and TE lineage samples for both methylome and transcriptome analyses.

RESULTS

Significant differential methylation and transcription was observed concurrently in ICM and TE lineages of APA-derived blastocysts compared to those from young fathers. The methylome revealed significant enrichment for neuronal signaling pathways, as well as an association with neurodevelopmental disorders and imprinted genes, largely overlapping within both the ICM and TE lineages. Significant enrichment of neurodevelopmental signaling pathways was also observed for differentially expressed genes, but only in the ICM. In stark contrast, no significant signaling pathways or gene ontology terms were identified in the trophectoderm. Despite normal semen parameters in aged fathers, these significant molecular alterations can adversely contribute to downstream impacts on offspring health, in particular neurodevelopmental disorders like autism spectrum disorder and schizophrenia.

CONCLUSIONS

An increased risk for neurodevelopmental disorders is well described in children conceived by aged fathers. Using blastocysts derived from donor oocyte IVF cycles to strategically control for maternal age, our data reveals evidence of methylation dysregulation in both tissue lineages, as well as transcription dysregulation in neurodevelopmental signaling pathways associated with APA fathers. This data also reveals that embryos derived from APA fathers do not appear to be compromised for initial implantation potential with no significant pathway signaling disruption in trophectoderm transcription. Collectively, our work provides insights into the complex molecular mechanisms that occur upon paternal aging during the first lineage differentiation in the preimplantation embryo. Early expression and epigenetic markers of APA-derived preimplantation embryos highlight the susceptibility of the future fetus to adverse health outcomes.

Li-Fraumeni syndrome presenting with de novo TP53 mutation, severe phenotype and advanced paternal age: a case report

BACKGROUND

Li-Fraumeni syndrome (LFS) is an autosomal dominant hereditary cancer syndrome caused by pathogenic variants in the gene TP53. This gene codes for the P53 protein, a crucial player in genomic stability, which functions as a tumor suppressor gene. Individuals with LFS frequently develop multiple primary tumors at a young age, such as soft tissue sarcomas, breast cancer, and brain tumors.

CASE PRESENTATION

A 38 years-old female with a history of femur osteosarcoma, ductal carcinoma of the breast, high-grade breast sarcoma, pleomorphic sarcoma of the left upper limb, infiltrating lobular carcinoma of the breast, gastric adenocarcinoma, leiomyosarcoma of the right upper limb, and high-grade pleomorphic renal sarcoma. Complete molecular sequencing of the TP53 gene showed c.586 C > T (p.R196X) in exon 6, which is a nonsense mutation that produces a shorter and malfunctioning P53. Family history includes advanced father's age at the time of conception (75 years), which has been associated with an increased risk of de novo germline mutations. The patient had seven paternal half-siblings with no cancer history. The patient received multiple treatments including surgery, systemic therapy, and radiotherapy, but died at the age of 38.

CONCLUSIONS

Advanced paternal age is a risk factor to consider when hereditary cancer syndrome is suspected. Early detection of hereditary cancer syndromes and their multi-disciplinary surveillance and treatment is important to improve clinical outcomes for these patients. Further investigation of the relationship between the pathogenic variant of TP53 and its phenotype may guide the stratification of surveillance and treatment.

Impact of male age on paternal aneuploidy: single-nucleotide polymorphism microarray outcomes following blastocyst biopsy

RESEARCH QUESTION

Does advanced paternal age (APA; ≥40 years) contribute to a higher incidence of paternal origin aneuploidy in preimplantation embryos?

DESIGN

This was a multicentre retrospective study of single-nucleotide polymorphism (SNP) microarray (Natera and Karyomapping) preimplantation genetic testing (PGT) outcomes of blastocyst-stage embryos. Whole-chromosome aneuploidy analysis was performed on 2409 embryos from 389 male patients undertaking 681 assisted reproductive technology (ART) cycles between 2012-2021. Segmental aneuploidy analysis was performed on 867 embryos from 140 men undertaking 242 ART cycles between 2016-2021. Embryos were grouped based on paternal age at sperm collection: <35, 35-39 and ≥40 years. Paternal and maternal origin aneuploidy rates were compared between groups using chi-squared and/or Fisher's exact tests.

RESULTS

There was no significant difference across groups in paternal origin whole-chromosome aneuploidy rate, overall (P=0.7561) or when segregated by type (trisomy and monosomy: P=0.2235 and 0.8156) or complexity (single versus 2, 3 or ≥4 aneuploidies: P=0.9733, 0.7517, 0.669 and 0.1481). Conversely, maternal origin whole-chromosome aneuploidy rate differed across groups (P<0.0001) in alignment with differing mean maternal age (P<0.001). Paternal origin deletions were 2.9-fold higher than maternal origin deletions (P=0.0084), independent of age stratification. No significant difference in paternal origin deletions was observed with APA ≥40 compared with the younger age groups (4.8% versus 2.5% and 2.8%, P=0.5292). Individual chromosome aneuploidy rates were too low to perform statistical comparisons.

CONCLUSIONS

No significant association was found between APA and the incidence of paternal origin aneuploidy in preimplantation embryos, irrespective of type or complexity. Thus, APA may not be an indication for PGT.

Semen parameters' mediation effect on the association between advanced paternal age and IVF clinical outcomes: A 10-year retrospective cohort study

OBJECTIVE

To explore the mediation between advanced paternal age and the outcomes of in vitro fertilization (IVF) in a female-adjusted cohort.

METHODS

The study retrospectively included couples undergoing IVF cycles between 2011 and 2020, and whose female partner was free of medical conditions that would significantly worsen clinical outcomes. Data on patient medical conditions, clinical data, and follow-up information were collected. Causal mediation effect analysis adopting both linear/logistic regression and mixed-effects models was carried out to evaluate the effect of paternal age on the outcomes.

RESULTS

21,959 IVF cycles were included in the study. Semen volume, sperm motility and sperm morphology were significantly associated (P value <0.05) with paternal age. A lower fertilization rate was associated with increased paternal age after adjustment for maternal age (adjusted OR = 0.800; 95 % CI, 0.678, 0.943; P value = 0.008). Mediation analysis revealed that A-level sperm rate and progressive rate respectively mediated 37.0 % and 41.0 % of the association between paternal age and fertilization rate.

CONCLUSION

Sperm motility rate, especially A-level sperm rate and rapid progressive rate, mediated the association between advanced paternal age and lower fertilization rate in the cycles.

Advanced Paternal Age Affects the Sperm DNA Fragmentation Index and May Lead to Lower Good-quality Blastocysts

Several studies show reductions in some seminal parameters in aged men and describe them as a consequence of many age-dependent changes in male organisms. This study aims to evaluate the impact of age on seminal parameters, particularly the DNA fragmentation index (DFI), and outcomes after in vitro fertilization (IVF) cycles. This is a retrospective study that includes 367 patients who underwent sperm chromatin structure assay testing between 2016 and 2021. The participants were split into three groups according to age: < 35 years (younger group, n = 63), 35-45 years (intermediate group, n = 227), and ≥ 45 years (older group, n = 77). The mean DFI (%) was compared. Among all patients, 255 received IVF cycles after DFI evaluation. For these patients, the sperm concentration, motility, and volume, as well as the fertilization rate, mean oocyte age, and good-quality blastocyst formation rate, were analyzed. One-way ANOVA was applied. The older group showed a significantly higher sperm than did the younger group (28.6% vs. 20.8% p = 0.0135). Despite not presenting a significant difference, the DFI level tends to be inversely related to good-quality blastocyst formation since the oocyte age was similar between the groups (32.0 v.s 33.6 vs. 32.3 years, respectively, p = 0.1183). Among aged men, the sperm DFI level is increased but other seminal parameters are not modified. Considering that men with a high sperm DFI can present some degree of infertility due to high sperm chromatin damage, male age should also be considered a limiting factor of IVF.

The effect of advanced paternal age on the lifespan of male offspring in an ancient Chinese genealogical data set

BACKGROUND

Advanced paternal age has been reported to be associated with a variety of short-term outcomes in offspring, but long-term effects are rarely examined. The present study evaluated the impact of advanced paternal age on offspring's longevity.

METHODS

We studied the effect of paternal reproductive age on the lifespan of male offspring using a Chinese genealogy data set that spans 226 years of the Qing Dynasty (1683-1909). Multivariable-adjusted Cox regression analyses of 1274 men with survival data were used to calculate hazard ratios (HRs) of advanced parental age at reproduction. We also evaluated whether the lifespan of brothers differed when they were born to the same parents at different ages.

RESULTS

In models adjusted for maternal age, advanced paternal age was negatively associated with the lifespan of male offspring. Individuals born to fathers aged >40 years had a 32 % higher HR of a lifespan shorter than those born to fathers aged 25-29 years (adjusted HR 1.320, 95 % CI: 1.066-1.634). The adjusted HR for offspring born to fathers aged 35-39 years was 1.232 (95 % CI: 1.013-1.500). Older brothers born to fathers aged 20-34 years had a significantly lower risk of a reduced lifespan compared with their younger brothers with fathers aged ≥35 years at reproduction (P < 0.01).

CONCLUSION

Advanced paternal age at reproduction is a negative factor for male offspring's life expectancy. With the sustained increase in paternal age over the past generation, further investigation is warranted into the impact on birth outcomes and public health.

The risky business of advanced paternal age: neurodevelopmental and psychosocial implications for children of older fathers

The last several decades are notable for an increase in the percentage of births attributable to men in their 40s and 50s. There is general recognition of offspring health risks related to advanced maternal age, however, fewer patients and providers are informed about the impacts of advanced paternal age (APA). This review examined the literature investigating the association between APA and offspring outcomes, specifically, neurodevelopmental, psychiatric, academic, and behavioral impairment, the impact of paternal health decline and death, and the influence of age on parenting behaviors. This analysis revealed that children, and even grandchildren, of older fathers face significantly increased incidence rates of psychiatric disease and behavioral impairment. The data do not show evidence of superior parenting behaviors among men with APA. Finally, children of men with APA are significantly more likely to experience early bereavement, which is associated with psychological and developmental consequences. An understanding of the degree to which APA can negatively impact the offspring is imperative for patient counseling and development of practice guidelines.

Reprint of: Advanced paternal age and risk of schizophrenia in offspring - Review of epidemiological findings and potential mechanisms

A large number of studies have examined the association between advanced paternal age (APA) and risk of schizophrenia in offspring. Here we present an overview of epidemiological studies on this subject published since 2000, and systematically summarize their methodologies and results. Next, we discuss evidence to elucidate the potential mechanisms contributing to the association between APA and offspring schizophrenia, considering paternal psychiatric morbidity and genetic liability, maternal factors, and findings from family design studies. We propose that multiple mechanisms, including causal and non-causal pathways, contribute to the observed relationship between APA and schizophrenia in offspring, and conclude by highlighting the need for multi-disciplinary studies in disentangling these complex, non-mutually exclusive mechanisms.

OBGYN providers' lack of knowledge and management of genetic risks due to advanced paternal age underscore the need for updated practice guidance

The objective of this pilot study was to characterize healthcare professionals' knowledge of advanced paternal age (APA), the associated risks, as well as current clinical practices regarding APA. Our study utilized an online survey that questioned providers who see children with genetic conditions and patients who are or may become pregnant regarding demographic information, APA knowledge, APA guideline familiarity, and their clinical practices. A total of 67 providers responded to the survey. We had responses from 54 physician participants in the specialties of medical genetics (GEN), maternal fetal medicine (MFM), and obstetrics and gynecology (OBGYN). OBGYN, but not MFM, reported significantly lower agreement that current data supports an association between APA and certain genetic diseases compared to GEN. Furthermore, OBGYN were less likely to identify established risks associated with APA and more likely to incorrectly identify unestablished risks compared to GEN and MFM. Regardless of specialty, the majority of physicians were unfamiliar with the most recently published APA guidelines. This study revealed a desire for more information regarding APA risks and management among our participants. Our data suggest that GEN, MFM, and OBGYN would benefit from updated and more visible guidelines regarding APA. Additionally, OBGYN consistently showed knowledge gaps and misconceptions regarding the risks of APA. Targeted educational or guidance materials regarding APA may also be beneficial for OBGYNs.

Awareness of paternal age effect disorders among Japanese pregnant women: implications for prenatal genetic counseling for advanced paternal age

The increasing prevalence of advanced paternal age (APA) has mirrored the rise in maternal age. APA is associated with an increased risk of de novo pathogenic single-nucleotide variants, but this topic has been much less frequently discussed than advanced maternal age (AMA). To explore the awareness of pregnant women regarding paternal age effect (PAE) disorders, a self-administered questionnaire survey was conducted for pregnant women at their first prenatal visit before 17 weeks of gestation. A total of 120 valid respondents (95.2%) were included in the analyses. Of these, 63.3% of pregnant women were aware of PAE disorders. This was markedly lower than the 90.8% recognition of maternal age effect (MAE) disorders. One-third of women with awareness of MAE disorders were not aware of PAE disorders. Pregnant women who were parous, older than their male partners, with knowledge of prenatal testing prior to this pregnancy, and with experience of prenatal testing in a prior pregnancy were significantly more aware of PAE disorders than others. Awareness of PAE disorders was not associated with undergoing prenatal testing during the present pregnancy. Our results show that the prevalence of pregnant women's awareness of PAE disorders was lower than that of MAE disorders. The current study served as a preliminary baseline of information about pregnant women's awareness of PAE disorders. With the introduction of non-invasive prenatal testing, which has the potential to identify PAE disorders, these findings will help the development of a framework for comprehensive prenatal genetic counseling for APA pregnancies.

Altered sperm tsRNAs in aged male contribute to anxiety-like behavior in offspring

Parental age at first pregnancy is increasing worldwide. The offspring of aged father has been associated with higher risk of several neuropsychiatric disorders, such as schizophrenia and autism, but the underlying mechanism remains elusive. Here we report that advanced paternal age in mice alters the profile of transfer RNA‐derived small RNAs (tsRNAs). Injection of sperm tsRNAs from aged male mice into zygotes induced anxiety‐like behaviors in F1 males. RNA sequencing of the cerebral cortex and hippocampus of those F1 male mice altered the gene expression of dopaminergic synapse and neurotrophin. tsRNAs from aged male mice injection also altered the neuropsychiatry‐related gene expression in two‐cell and blastocyst stage embryos. More importantly, the sperm tsRNA profile changes significantly during aging in human. The up‐regulated sperm tsRNA target genes were involved in neurogenesis and nervous system development. These results suggest that aging‐related changes of sperm tsRNA may contribute to the intergenerational transmission of behavioral traits.

Advanced paternal age and risk of schizophrenia in offspring - Review of epidemiological findings and potential mechanisms

A large number of studies have examined the association between advanced paternal age (APA) and risk of schizophrenia in offspring. Here we present an overview of epidemiological studies on this subject published since 2000, and systematically summarize their methodologies and results. Next, we discuss evidence to elucidate the potential mechanisms contributing to the association between APA and offspring schizophrenia, considering paternal psychiatric morbidity and genetic liability, maternal factors, and findings from family design studies. We propose that multiple mechanisms, including causal and non-causal pathways, contribute to the observed relationship between APA and schizophrenia in offspring, and conclude by highlighting the need for multi-disciplinary studies in disentangling these complex, non-mutually exclusive mechanisms.

High-resolution analyses of human sperm dynamic methylome reveal thousands of novel age-related epigenetic alterations

Background

Children of aged fathers are at a higher risk of developing mental disorders. Alterations in sperm DNA methylation have been implicated as a potential cause. However, age-dependent modifications of the germ cells’ epigenome remain poorly understood. Our objective was to assess the DNA methylation profile of human spermatozoa during aging.

Results

We used a high throughput, customized methylC-capture sequencing (MCC-seq) approach to characterize the dynamic DNA methylation in spermatozoa from 94 fertile and infertile men, who were categorized as young, 48 men between 18–38 years or old 46 men between 46–71 years. We identified more than 150,000 age-related CpG sites that are significantly differentially methylated among 2.65 million CpG sites covered. We conducted machine learning using our dataset to predict the methylation age of subjects; the age prediction accuracy based on our assay provided a more accurate prediction than that using the 450 K chip approach. In addition, we found that there are more hypermethylated (62%) than hypomethylated (38%) CpG sites in sperm of aged men, corresponding to 798 of total differential methylated regions (DMRs), of which 483 are hypermethylated regions (HyperDMR), and 315 hypomethylated regions (HypoDMR). Moreover, the distribution of age-related hyper- and hypomethylated CpGs in sperm is not random; the CpG sites that were hypermethylated with advanced age were frequently located in the distal region to genes, whereas hypomethylated sites were near to gene transcription start sites (TSS). We identified a high density of age-associated CpG changes in chromosomes 4 and 16, particularly HyperDMRs with localized clusters, the chr4 DMR cluster overlaps PGC1α locus, a protein involved in metabolic aging and the chr16 DMR cluster overlaps RBFOX1 locus, a gene implicated in neurodevelopmental disease. Gene ontology analysis revealed that the most affected genes by age were associated with development, neuron projection, differentiation and recognition, and behaviour, suggesting a potential link to the higher risk of neurodevelopmental disorders in children of aged fathers.

Conclusion

We identified thousands of age-related and sperm-specific epigenetic alterations. These findings provide novel insight in understanding human sperm DNA methylation dynamics during paternal aging, and the subsequently affected genes potentially related to diseases in offspring.

Advanced parental age: Is it contributing to an increased incidence of non-syndromic craniosynostosis? A review of case-control studies

Background

Craniosynostosis (CS) is a congenital birth defect characterized by the premature fusion of one or several calvarial suture(s). CS could lead to serious complications, such as intracranial hypertension and neurodevelopmental impairment. There is an increasing trend in the prevalence of CS - 75% of which are of non-syndromic type (NSCS). In parallel, there is a steady rise in the average maternal age. The goal of this paper was to review the literature to clearly identify any associations between parental age and NSCS. This review was performed and reported in compliance with PRISMA guidelines.

Methods

The PUBMED and EMBASE databases were systematically searched, and all studies that observed the relationship between maternal and/or paternal age on NSCS were included. The articles were then assessed for methodological quality using the Newcastle-Ottawa Scale (NOS). The effect of advanced maternal and/or paternal age on the incidence of NSCS was identified by the prevalence ratios reported at a confidence interval of 95%.

Results

Six retrospective case-control studies, reporting on a total of 3267 cases of NSCS were included in this review. While there were some inconsistencies in the findings of the different studies, the majority reported a positive correlation between advanced maternal and/or paternal age and an increased incidence of NSCS.

Conclusion

This review identified an association between advanced parental age and an increased incidence of NSCS.

Understanding the association between advanced paternal age and schizophrenia and bipolar disorder

BACKGROUND

Previous studies reported an association between advanced paternal age at birth and increased risk for schizophrenia and bipolar disorder. While some hypothesize that this association is caused by de-novo mutations in paternal spermatozoa, others cite factors associated with psycho-social characteristics of fathers who have children at a late age. This study aims to test these hypotheses.

METHODS

A historical-prospective, population-based cohort study, performed by linking the Israeli Draft Board Registry and the Israeli National Psychiatric Hospitalization Registry (N = 916 439; 4488 with schizophrenia, 883 with bipolar disorder). Odds ratios (OR) and two-sided 95% confidence intervals (CI) were calculated by logistic regression models, using paternal age as predictor and risk for later hospitalizations for schizophrenia or bipolar disorder as outcome measure. Models were first fitted unadjusted, then adjusted for paternal age at birth of the first child.

RESULTS

In the unadjusted model, offspring of fathers aged 45 and above at birth had increased risk of schizophrenia (OR = 1.71, 95% CI 1.49-1.99) and bipolar disorder (OR = 1.63, 95% CI 1.16-2.24). However, taking into account paternal age at birth of first child, advanced paternal age was no longer associated with increased risk of schizophrenia (OR = 0.60, 95% CI 0.48-0.79) or bipolar disorder (OR = 1.03, 95% CI 0.56-1.90).

CONCLUSIONS

Controlling for paternal age at birth of the first offspring, advanced paternal age does not predict increased risk for schizophrenia or bipolar disorder. These data indicate that the association between advanced paternal age and having an offspring with schizophrenia and bipolar disorder is likely due to psychos-social factors, or common genetic variation associated with delayed initial fatherhood.

Advanced paternal age does not affect embryo aneuploidy following blastocyst biopsy in egg donor cycles

PURPOSE

To study the impact of advanced paternal age on embryo aneuploidy.

METHODS

This is a multicenter international retrospective case series of couples undergoing assisted reproduction via in vitro fertilization using donor eggs to control for maternal factors and preimplantation genetic testing for aneuploidy via next-generation sequencing at Igenomix reproductive testing centers. The main outcome measure was the prevalence of embryo aneuploidy in egg donor cycles. Semen analysis data was retrieved for a small subset of the male patients.

RESULTS

Data from 1202 IVF/ICSI egg donor cycles using ejaculated sperm (total 6934 embryos) evaluated using PGT-A between January 2016 and April 2018 in a global population across all Igenomix centers were included. No significant association was identified between advancing paternal age and the prevalence of embryo aneuploidy overall and when analyzing for each chromosome. There was also no significant association between advancing paternal age and specific aneuploid conditions (monosomy, trisomy, partial deletion/duplication) for all chromosomes in the genome.

CONCLUSIONS

This is the largest study of its kind in an international patient population to evaluate the impact of advancing paternal age on embryo aneuploidy. We conclude there is no specific effect of paternal age on the prevalence of embryo aneuploidy in the context of embryo biopsies from egg donor cycles.

Transgender men, pregnancy, and the "new" advanced paternal age: A review of the literature

Transgender men are assigned female at birth, but self-identify as male. Although some transgender men undergo gender-affirming hormonal treatment and/or surgery that preclude pregnancy, many (if not most) retain their female reproductive organs and, as a result, their capacity to become pregnant. Although the visibility of the transgender community has increased, the exposure of healthcare providers to transgender individuals, especially transgender men during pregnancy, as well as research that addresses evidence-based practice remain limited. In this review, we discuss obstetrical issues for transgender men who are ≥35 years old, termed the "new" advanced paternal age. We review preconception care and focus on fertility issues, the impact of stopping gender-affirming hormonal treatment, and age-appropriate health maintenance. We review antepartum and postpartum care, including labor and delivery, monitoring for perinatal depression, contraception, and chest feeding. Finally, we conclude with suggestions for areas for further research and study.

Parental age and stillbirth: a population-based cohort of nearly 10 million California deliveries from 1991 to 2011

PURPOSE

Parental age at delivery in the United States has been rising. Advanced maternal and paternal ages have been associated with adverse pregnancy outcomes including stillbirth. However, these relationships come from studies that often do not present results for both mother and father concurrently. The purpose of this study was to estimate the risk of stillbirth for maternal and paternal age in the same cohort of deliveries.

METHODS

This is a population-based cohort study of all live birth and stillbirth deliveries in California from 1991 to 2011. The individual associations between maternal and paternal ages and stillbirth were estimated with hazard ratios from Cox proportional hazard models. Age was modeled continuously with restricted cubic splines to account for nonlinear relationships. Mean parental age was used as the referent group.

RESULTS

J-shaped associations between maternal and paternal ages were observed in crude models where older mothers and fathers had the highest hazard ratios for stillbirth. In maternal models, after adjusting for maternal and paternal covariates, young maternal age no longer showed increased hazard ratio for stillbirth, whereas the association with older mothers remained. In adjusted paternal models, the relationship between young paternal age and stillbirth was unchanged while the hazard ratio for older fathers was slightly smaller.

CONCLUSIONS

After adjusting for both parents' age, education, race/ethnicity, along with parity, older mothers and fathers were independently associated with elevated hazard ratios for stillbirth.

Reproductive genetics and the aging male

PURPOSE

To examine current evidence of the known effects of advanced paternal age on sperm genetic and epigenetic changes and associated birth defects and diseases in offspring.

METHODS

Review of published PubMed literature.

RESULTS

Advanced paternal age (> 40 years) is associated with accumulated damage to sperm DNA and mitotic and meiotic quality control mechanisms (mismatch repair) during spermatogenesis. This in turn causes well-delineated abnormalities in sperm chromosomes, both numerical and structural, and increased sperm DNA fragmentation (3%/year of age) and single gene mutations (relative risk, RR 10). An increase in related abnormalities in offspring has also been described, including miscarriage (RR 2) and fetal loss (RR 2). There is also a significant increase in rare, single gene disorders (RR 1.3 to 12) and congenital anomalies (RR 1.2) in offspring. Current research also suggests that autism, schizophrenia, and other forms of "psychiatric morbidity" are more likely in offspring (RR 1.5 to 5.7) with advanced paternal age. Genetic defects related to faulty sperm quality control leading to single gene mutations and epigenetic alterations in several genetic pathways have been implicated as root causes.

CONCLUSIONS

Advanced paternal age is associated with increased genetic and epigenetic risk to offspring. However, the precise age at which risk develops and the magnitude of the risk are poorly understood or may have gradual effects. Currently, there are no clinical screenings or diagnostic panels that target disorders associated with advanced paternal age. Concerned couples and care providers should pursue or recommend genetic counseling and prenatal testing regarding specific disorders.

Infertility in the Aging Male

PURPOSE OF REVIEW

In many countries, the average age of paternity is rising. The negative effect of older age on fertility in women is well documented; however, less is known about the impact of paternal age on fecundity. In this review, we summarize the current knowledge of how paternal age affects semen parameters, reproductive success, and offspring health.

RECENT FINDINGS

Contemporary evidence confirms that aged men have worse semen parameters, including overall negative changes in sperm genetics. Reproductive outcomes with unassisted pregnancy tend to be worse with older fathers. While most current studies of assisted pregnancy do show a negative effect of paternal age, there are some conflicting results. Studies continue to show an overall increased risk of health problems, particularly neuropsychiatric conditions, in the offspring of older men. While men can often maintain fertility potential throughout a lifetime, increasing evidence indicates worsening of semen parameters, including sperm genetics, and potentially worse reproductive success. Older men should also be counseled on their offspring's possible increased risk of certain medical conditions.

Children born to mothers in their 20s and fathers in their 40s: Evidence for an increased low birth weight and Cesarean Section deliveries in Lebanon

PURPOSE

Much less is known about the effect of advanced paternal age (APA) (≥40 years) than advanced maternal age on neonatal morbidity. More specifically, the correlation with low birth weight remains inconsistent. This study aims to determine whether APA among mothers aged 20-29 years is associated with a higher risk of low birth weight and other neonatal outcomes.

METHODS

Data from 2004 to 2008 database of the National Collaborative Perinatal Neonatal Network were used. Fifteen thousand two hundred eighteen live birth singleton pregnancies by primigravida mothers aged 20-29 years were analyzed. Study variables include paternal age (years), C-section delivery (yes/no), low birth weight (<2500 g), and preterm births (<37 weeks of gestation). Regressions were generated controlling for birth defects, consanguinity, maternal education, prenatal care, gender, and maternal smoking.

RESULTS

Adjusted odds of Low Birth Weight (LBW) and Cesarean Section Deliveries (CSD) were significantly higher in infants of APA fathers compared to those of fathers aged 30-35 years [adjusted odds ratio (95% confidence interval) = 1.5 (1.1, 2.3) and 1.4 (1.1, 1.7), respectively]. Paternal ages of 35-39 years compared to less than 30 years were associated with higher odds of CSD [adjusted odds ratio = 1.4 (1.2, 1.5)]. APA was not associated with preterm birth after adjustment.

CONCLUSIONS

This study supports the association between APA and increased risk for LBW and CSD.

The effect of parental age on NF1 patients in Turkey

Neurofibromatosis type 1 (NF1) is the most common neurogenetic disorder worldwide, and its clinical presentations are highly variable. NF1 is caused by mutations in the NF1 gene, and 50% of NF1 cases are sporadic, which occur in the absence of a family history of the disease and usually result from a new mutation in the germline of a parent. Advanced paternal age may increase the risk for germinal NF1 mutations; however, some dominant conditions, including neurofibromatosis, have shown a lesser association with paternal age, although there are conflicting reports in the literature. We investigated the effects of paternal and maternal age in 241 NF1 patients (121 sporadic and 120 familial cases) who were seen in Hacettepe hospital, a reference center for genetic diseases in Turkey. For statistical analysis, Spearman's and Chi-square tests were used. In this study, we evaluated paternal and maternal age at birth in sporadic and familial cases of NF1. We also compared the effect of parental age on the appearance and coexistence of various NF1 symptoms. There were no significant statistical differences between paternal age and coexistence of the NF1 symptoms. However, a slightly negative correlation was observed between paternal age and the coexistence of NF1 symptoms in familial cases (p < 0.05). We did not find strong evidence for the effect of parental age on the clinical severity of NF1.

The effect of parental age on the presence of de novo mutations - Lessons from neurofibromatosis type I

Background

Neurofibromatosis type 1 (NF1) is the most common autosomal dominant neurocutaneous disease with a prevalence of 1:2500. Approximately, 50% of the cases are sporadic. Advanced paternal age is associated with germline mutations and autosomal diseases. We aimed to use NF1 as a paradigm to study the effect of parental age on sporadic mutation rates for both advanced and younger parental ages.

Methods

The medical charts of 118 NF1 pediatric patients followed in a specialized Israeli NF1 clinic were evaluated. Thirty‐one cases were diagnosed by genetic tests and 87 by NIH clinical criteria. Sixty‐four cases (54%) had a negative family history of NF1 (sporadic cases). Data on parental ages at the time of the children's birth were compared to the national population database.

Results

Parental age of children with sporadic NF1 was higher than the general population (32.7 years vs. 30.1 years, respectively, for the mothers and 36.5 years vs. 32.6 years, respectively, for the fathers; P < 0.0001 for both groups). In contrast, the age of the mothers and the fathers in the familial cases (30.3 and 33.9 years, respectively) did not differ from the general population. Significantly, fewer fathers of the sporadic group had been 25–29 years old at their child's birth compared with fathers in the general population (7.8% vs. 21%, respectively, P = 0.009), and significantly more fathers were ≥40 years old (29.7% vs. 13.6%, respectively, P = 0.0002). Differences in maternal age between these two groups were less prominent.

Conclusion

Parents of sporadic NF1 cases are older. The risk for sporadic NF1 was lower when the fathers were younger at the time of the affected child's birth, and gradually increased with paternal age.

Paternal aging and associated intraindividual alterations of global sperm 5-methylcytosine and 5-hydroxymethylcytosine levels

OBJECTIVE

To evaluate the relative intraindividual changes in sperm 5-methylcytosine (5-mC) and 5-hydroxymethylcytosine (5-hmC) levels associated with age and to compare the levels of 5-hmC in mature human sperm to blood DNA.

DESIGN

Prospective research study.

SETTING

University-based andrology and in vitro fertilization (IVF) laboratory.

PATIENT(S)

Fifteen known fertile sperm donors, 22 other known fertile controls, and 41 male blood donors from a general population tissue bank.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Measurements of global 5-mC and 5-hmC levels via an enzyme-linked immunosorbent assay (ELISA)-based assay.

RESULT(S)

Global sperm 5-mC levels exhibit a statistically significant increase with age, and a similar trend was seen in 5-hmC levels. On average, in the age ranges we analyzed, 5-mC increased by 1.76% per year, and 5-hmC, though more variable, increased by approximately 5% per year. Additionally, we found that 5-hmC levels in sperm are 32.59% of that found in blood DNA.

CONCLUSION(S)

Global sperm DNA methylation patterns are stable over short periods of time but increase with age, which raises important questions regarding the risks of advanced paternal age. Additionally, as we would predict for a transcriptionally quiescent cell type, 5-hmC levels are statistically significantly lower in human sperm than in blood DNA.