Assessment of sperm using mRNA microarray technology

Clusterin expression and distribution in spermatozoa as predictor of male fertility

Clusterin (CLU), one of the main glycoproteins in mammalian semen and the male reproductive tract, plays a role in spermatogenesis and sperm maturation. Given the poor reliability of classic seminal studies in determining male-fertilizing capacity and the differences in CLU abundance between normal and abnormal spermatozoa, we investigated the potential value of mRNA-CLU levels and protein distribution in spermatozoa as markers of sperm quality and predictors of male fertility. This multicenter study included 90 patients undergoing in vitro fertilization (IVF) treatment with their partners, and a control group of 36 fertile males with normal seminograms. We assessed the relationship between IVF treatment outcomes, seminogram variables, mRNA-CLU levels by quantitative real-time-PCR and CLU distribution by immunostaining in spermatozoa. Our study reveals CLU staining in the acrosome (p = 0.002, OR 14.8, 95% CI: 2.7-79.3) and mRNA-CLU levels (p = 0.005, OR 10.85, 95% CI: 2.0-57.4) as independent risk factors for pregnancy failure, irrespective of traditional seminogram variables. Additionally, our results suggest that CLU, and specially its secreted isoform, constitutes a component of the protein pool that human spermatozoa can produce during its maturation process, exhibiting a variable abundance and distribution in spermatozoa from fertile men compared to those in patients with altered seminograms and infertile patients with normal seminograms. Our study is the first to identify mRNA-CLU levels and CLU immunostaining in the spermatozoa acrosome as independent risk factors for pregnancy failure, with distribution patterns correlating with sperm maturity and seminogram alterations.

Obstetrical and Perinatal Outcomes Are Not Associated with Advanced Paternal Age in IVF or ICSI Pregnancies with Autologous Oocytes

BACKGROUND

In recent years, there has been an evident delay in childbearing and concerns have been raised about whether this increase in age affects reproductive outcomes. This study aimed to evaluate the effect of paternal age on obstetrical and perinatal outcomes in couples undergoing in vitro fertilization or intracytoplasmic sperm injection using autologous sperm and oocytes.

METHODS

This retrospective study evaluated obstetrical and perinatal outcomes from 14,125 couples that were arbitrarily divided into three groups according to paternal age at conception: ≤30 (n = 1164), 31-40 (n = 11,668) and >40 (n = 1293). Statistics consisted of a descriptive analysis followed by univariate and multivariate models, using the youngest age group as a reference.

RESULTS

The study showed significantly longer pregnancies for the fathers aged 31-40 compared to ≤30 years. However, there were no significant differences for the type of delivery, gestational diabetes, anaemia, hypertension, delivery threat, premature rupture of membranes, preterm birth, very preterm birth, and the neonate's sex, weight, low birth weight, very low birth weight, length, cranial perimeter, Apgar score and neonatal intensive care unit admission.

CONCLUSION

Despite our promising results for older fathers, as paternal age was not associated with clinically relevant obstetrical and perinatal outcomes, future well-designed studies are necessary as it has been associated with other important disorders.

Sperm epigenetics landscape: correlation with embryo quality, reproductive outcomes and offspring's health

Epigenetics refers to how gene expression and function are modulated without modifying the DNA sequence but through subtle molecular changes or interactions with it. As spermatogenesis progresses, male germ cells suffer plenty of epigenetic modifications, resulting in the definitive epigenome of spermatozoa conditioning its functionality, and this process can be altered by several internal and external factors. The paternal epigenome is crucial for sperm function, fertilization, embryo development, and offspring's health, and altered epigenetic states are associated with male infertility with or without altered semen parameters, embryo quality impairment, and worse ART outcomes together with the future offspring's health risks mainly through intergenerational transmission of epigenetic marks. Identifying epigenetic biomarkers may improve male factor diagnosis and the development of targeted therapies, not only to improve fertility but also to allow an early detection of risk and disease prevention in the progeny. While still there is much research to be done, hopefully in the near future, improvements in high-throughput technologies applied to epigenomes will permit our understanding of the underlying epigenetic mechanisms and the development of diagnostics and therapies leading to improved reproductive outcomes. In this review, we discuss the mechanisms of epigenetics in sperm and how epigenetics behave during spermatogenesis. Additionally, we elaborate on the relationship of sperm epigenetics with sperm parameters and male infertility, and highlight the impact of sperm epigenetic alterations on sperm parameters, embryo quality, ART outcomes, miscarriage rates and offspring's health. Furthermore, we provide insights into the future research of epigenetic alterations in male infertility.

Sperm mRNAs as potential markers of male fertility

Advances in transcriptomic technologies are contributing to an increased understanding of the role of spermatozoal RNA in sperm physiology. Although sperm transcriptomic studies have delivered large amounts of valuable information, no new male fertility biomarkers have emerged from such studies to date. This review summarizes current knowledge about the potential relevance of certain mRNA as biomarkers, focusing on comparative studies of human spermatozoa transcriptomic profiles from fertile and pathological semen samples. Asthenozoospermia is the semen aberrant condition that has been most exhaustively investigated to date. We cross-analyzed findings from three different studies on the transcriptome of asthenozoospermic semen samples and identified 100 transcripts that were consistently differentially expressed and that consequently are candidates for characterizing the molecular source of this sperm anomaly. The potential use of sperm mRNAs as predictors of outcomes of assisted reproductive technologies (ART) is also reviewed. Improving the understanding of the human spermatozoa mRNA content is expected to improve the evaluation and diagnosis of infertile men, and ultimately facilitate the selection of the best treatment to overcome infertility.

Gene transcription profiling of astheno- and normo-zoospermic sperm subpopulations

Spermatozoa contain a repertoire of RNAs considered to be potential functional fertility biomarkers. In this study, the gene expression of human sperm subpopulations with high (F1) and low (F2) motility from healthy normozoospermic (N) and asthenozoospermic (A) individuals was evaluated using RNA microarray followed by functional genomic analysis of differentially expressed genes. Results from A–F1 versus N–F1, A–F2 versus N–F2, N–F1 versus N–F2, and A–F1 versus A–F2 comparisons showed a considerably larger set of downregulated genes in tests versus controls. Gene ontology (GO) analysis of A–F1 versus N–F1 identified 507 overrepresented biological processes (BPs), several of which are associated with sperm physiology. In addition, gene set enrichment analysis of the same contrast showed 110 BPs, 36 cellular components, and 31 molecular functions, several of which are involved in sperm motility. A leading-edge analysis of selected GO terms resulted in several downregulated genes encoding to dyneins and kinesins, both related to sperm physiology. Furthermore, the predicted activation state of asthenozoospermia was increased, while fertility, cell movement of sperm, and gametogenesis were decreased. Interestingly, several downregulated genes characteristic of the canonical pathway protein ubiquitination were involved in asthenozoospermia activation. Conversely, GO analysis of A–F2 versus N–F2 did not identify overrepresented BPs, although the gene set enrichment analysis detected six enriched BPs, one cellular component, and two molecular functions. Overall, the results show differences in gene transcription between sperm subpopulations from asthenozoospermic and normozoospermic semen samples and allowed the identification of gene sets relevant to sperm physiology and reproduction.

Differential sperm proteomic profiles according to pregnancy achievement in intracytoplasmic sperm injection cycles: a pilot study

PURPOSE

To describe the proteomic profiles in semen samples and define the differences in sperm proteomic profiles among samples that ultimately achieved pregnancy (P) via intracytoplasmic sperm injection (ICSI) in an oocyte donation program and those that were unsuccessful (NP).

METHODS

Prospective, analytical, observational nested case and control study evaluating the proteomic profile of spermatozoa from patients' ejaculates where pregnancies were (group pregnant (P), n= 4) or were not (group non-pregnant (NP), n=4) achieved after ICSI in an oocyte donation program aiming to standardize female factor. Proteins were separated and analyzed by means of SWATH-MS) and compared between P/NP groups to identify sperm biomarkers of fertility/infertility. Proteins are available via ProteomeXchange.

RESULTS

We identified and quantified 2228 proteins, with 37 significantly higher in the P group and 16 higher in NP. Enrichment analysis revealed that the increased proteins in P group sperm were related to motility, anaerobic metabolism, and protein biosynthesis functions, while the increased proteins in the NP group were involved in protein biosynthesis, protein folding, aerobic metabolism, and signal transduction, all of which are functions not previously described as influencing sperm success. Some proteins identified (e.g., SLC2A3, or CD81) are located in the cell membrane and thus may be employed to select spermatozoa by magnetic-activated cell sorting (MACS).

CONCLUSION(S)

This work revealed differences in the proteomic profiles of sperm samples successful in achieving pregnancy and those that were not, expanding our understanding of sperm function and infertility-related molecular markers, and enabling the future development of male fertility diagnostic tools and therapies.

Personalized Medicine in Infertile Men

Personalized medicine gathers the most relevant data involved in human health. Currently, the diagnosis of male infertility is limited to spermiogram, which does not provide information on the male fertile potential. New diagnostic methods are required. The application of omics techniques in the study of male reproductive health renders a huge amount of data providing numerous novel infertility biomarkers, from genes to metabolites, to diagnose the cause of male infertility. Recent studies hold the promise that these biomarkers will allow a noninvasive infertility diagnosis and the improvement of the sperm selection techniques.

Cutting Edge of Reproductive Medicine

Background: Louise Brown’s delivery in 1978 was the mark of a successful IVF program that has now been in practice for more than 40 years. The technology has delivered more than 8 million babies. Many breakthrough innovations were established to answer the problem in ART services. Optimizing ART biomarkers and cross border reproductive care have become a rising issue in ART services. Disruptive innovation disrupts the existing condition and takes the lead in the new market, including to change our patient behavior in health services. National health services addressed new issues about the impact of 4.0 industrial revolution on health workforce and our daily practices. Every disruptive innovation today is enhanced by a combination of physical, digital, and biological domain. The advancement in the area of the internet of things, artificial intelligence, virtual reality, nanotechnology, cloud computing, big data, deep learning, machine learning, robotics, and gene editing could potentially support us to innovate. And to improve the quality and outcome of ART, the introduction of the latest technology, such as robotics and artificial intelligence, has become an essential approach. A recent study discovered that the use of artificial intelligence would remove the embryologist’s subjectivity and improve the way we choose the best embryo for implantation. The next challenging issue in ART is improving the success rate through optimizing noninvasive biomarkers development. Many biological products such as blood, tissue, organ fluid can be assessed and considered to be used as IVF biomarkers. Proteomic tools were used and are needed to analyze a sample from subjects before it was created as a biomarker for improving the IVF services quality.

Conclusion: The development of IVF over 40 years has brought about many distinct achievements in the laboratory and in clinic. Industrial revolution 4.0 has generated many innovations that have helped improve the quality of ART services, including AUGMENT social egg freezing, artificial intelligence, and genome editing. In this era, precision medicine looks very promising for bridging the gap and increasing the accuracy and efficacy of promotive, preventive, diagnostic, and treatment approaches in reproductive medicine.

Sperm lipidic profiles differ significantly between ejaculates resulting in pregnancy or not following intracytoplasmic sperm injection

Although assisted reproduction techniques involve the use of semen samples, there is little scientific methodology applied when selecting sperm. To select the most appropriate spermatozoa, first we need to define the optimal molecular characteristics. Sperm lipids may contribute to sperm function, thus our aim was to compare the lipidic profiles of sperm samples used in intracytoplasmic sperm injection cycles that ultimately led to a pregnancy with those that did not.Spermatozoa from infertile patients after intracytoplasmic sperm injection (group non-pregnant, n = 16; vs. group pregnant, n = 22) were analyzed for lipid composition using ultra-high performance liquid chromatography coupled to mass spectrometry, by means two platforms for measuring fatty acyls, bile-acids, lysoglycerophospholipids, glycerolipids, cholesteryl-esters, sphingolipids, and glycerophospholipids. Lipid levels were compared using a univariate test and multivariate analyses after logarithmic transformation.We detected 151 different lipids in the sperm samples, 10 of which were significantly increased in sperm samples from the NP group, ranging from 1.10- to 1.30-fold change. These were primarily ceramides, sphingomyelins and three glycerophospholipids, a lysophosphatidylcholine, and two plasmalogen species. Additionally, 2-Monoacylglycerophosphocholine were also found in higher levels in non-pregnant group.Our results describe the composition of sperm lipids linked to optimal sperm function, opening new possibilities for the development of male fertility diagnostic tools and culture media formulations to improve sperm quality and enhance reproductive results. Given that lipids compose the majority of the sperm plasma membrane, this information is also useful in designing new sperm selection tools that will allow for the selection of the best spermatozoa.

Advanced Paternal Age Affects Sperm Count and Anogenital Distance in Mouse Offspring

In Western society, couples increasingly delay parenthood until later in life. Overall, studies have focused on the reproductive performance of older parents or the impact of advanced maternal age on pregnancy outcomes, but few studies have examined how advanced paternal age (APA) affects offspring health. The aim of this study was to investigate the impact of increasing paternal age on offspring reproductive performance and long-term metabolic health in a mouse model. Here, the same adult B6D2F1/J male mice were mated at 4, 12, and 18 months of age with 6- to 10-week-old naturally cycling CF1 females to generate 3 offspring cohorts conceived at increasing paternal ages PA4, PA12, and PA18. The offspring resulting from mating the same fathers at different ages (n = 20 per age; 10 males and 10 females) were maintained up to 20 weeks of age and morphometric parameters, growth curve, and glucose tolerance were measured. We found that increasing paternal age was associated with a trend toward longer time to conception. Litter sizes were not significantly different. Reassuringly, metabolic parameters and growth curve were not different in the 3 cohorts of offspring. Most importantly, increased paternal age (PA4 vs PA18) was associated with a statistically significant decrease in sperm concentration, sperm motility, and anogenital distance in offspring. These changes raise concerns about the potential impact of APA on the reproductive fitness in males of the next generation.

Obstetric and perinatal outcome of babies born from sperm selected by MACS from a randomized controlled trial

PURPOSE

The purpose of this study is to assess outcomes after magnetic-activated cell sorting (MACS) technology on obstetric and perinatal outcomes compared with those achieved after swim up from randomized controlled trial.

METHODS

This is a two-arm, unicentric, prospective, randomized, and triple-blinded trial and has a total of 237 infertile couples, between October 2010 and January 2013. A total of 65 and 66 newborns from MACS and control group, respectively, were described.

RESULTS

MACS had no clinically relevant adverse effects on obstetric and perinatal outcomes. No differences were found for obstetric problems including premature rupture of membranes 6.1% (CI95% 0-12.8) vs. 5.9% (CI95% 0-12.4), 1st trimester bleeding 28.6% (CI95% 15.9-41.2) vs. 23.5% (CI95% 11.9-35.1), invasive procedures as amniocentesis 2.0% (CI95% 0-5.9) vs. 3.9% (CI95% 0-9.2), diabetes 14.3% (CI95% 4.5-24.1) vs. 9.8% (CI95% 1.6-17.9), anemia 6.1% (CI95% 0-12.8) vs. 5.9%(CI95% 0-12.4), 2nd and 3rd trimesters 10.2% (CI95% 1.7-18.7) vs. 5.9% (CI95% 0-12.4), urinary tract infection 8.2% (CI95% 0.5-15.9) vs. 3.9% (CI95% 0-9.2), pregnancy-induced hypertension 6.1% (CI95% 0-12.8) vs. 15.7% (CI95% 5.7-25.7), birth weight (g) 2684.10 (CI95% 2499.48-2868.72) vs. 2676.12 (CI95% 2499.02-2852.21), neonatal height (cm) 48.3 (CI95% 47.1-49.4) vs. 46.5 (CI95% 44.6-48.4), and gestational cholestasis 0%(CI95% 0-0) vs. 3.9% (CI95% 0-9.2), respectively, in MACS group compared with control group.

CONCLUSIONS

Our data suggest that MACS technology does not increase or decrease Powered by Editorial Manager® and ProduXion Manager® from Aries Systems Corporation adverse obstetric and perinatal outcomes in children conceived when this technology was performed, being the largest randomized control trial with live birth reported results with MACS.

Screening targeted testis‑specific genes for molecular assessment of aberrant sperm quality

Teratospermia is a heterogeneous and complex disorder, which is closely associated with male fertility. Genes and gene products associated with teratospermia may serve as targeted biomarkers that help understand the underlying mechanisms of male infertility; however, systematic information on the subject remains to be elucidated. The present study performed a comparative bioinformatics analysis to identify biomarkers associated with sperm quality, particular focusing on testis-specific biomarkers. A stepwise screening approach identified 1,085 testis/epididymis-specific genes and 3,406 teratospermia-associated genes, resulting in 348 testis-specific genes associated with aberrant sperm quality. These genes were functionally associated with the reproduction process. Gene products corresponding to heat shock protein family A (Hsp70) member 4 like (HSPA4L) and phosphoglycerate kinase 2 were characterized at the cellular level in human testes and ejaculated spermatozoa. HSPA4L expression in sperm was revealed to be associated with sperm quality. The present study provided a novel insight into the understanding of sperm quality, and a potential method for the diagnosis and assessment of sperm quality in the event of male infertility.

Increased N6-methyladenosine in Human Sperm RNA as a Risk Factor for Asthenozoospermia

Male infertility is a worldwide medical problem. Asthenozoospermia is a common cause of infertility. Epigenetic modifications of DNA and histones have been shown to influence human infertility, but no research has explored whether N(6)-methyladenosine (m(6)A) level in RNA is associated with asthenozoospermia. Here, we collected a total of 52 semen samples, including 20 asthenozoospermia patients and 32 healthy controls. An LC-ESI-MS/MS method was used to detect m(6)A contents in sperm RNA, and real-time PCR was performed to determine the mRNA expression of demethylase (FTO, ALKBH5), methyltransferase (METTL3, METTL14, WTAP) and an m(6)A-selective-binding protein (YTHDF2). We found that m(6)A content (p = 0.033) and the mRNA expression of METTL3 (p = 0.016) and METTL14 (p = 0.025) in asthenozoospermia patients were significantly higher than those of controls. Increased m(6)A content was a risk factor for asthenozoospermia (odds ratio (OR) 3.229, 95% confidence interval (CI) 1.178 - 8.853, p = 0.023). Moreover, m(6)A content was correlated with the expression of METTL3 (r = 0.303, p = 0.032) and with sperm motility (progressive motility: r = -0.288, p = 0.038; non-progressive motility: r = -0.293, p = 0.037; immotility: r = 0.387, p = 0.005). Our data suggest that increased m(6)A content is a risk factor for asthenozoospermia and affects sperm motility. Methyltransferases, particularly METTL3, play key roles in increasing m(6)A contents in sperm RNA.

Sperm selection in natural conception: what can we learn from Mother Nature to improve assisted reproduction outcomes?

BACKGROUND

In natural conception only a few sperm cells reach the ampulla or the site of fertilization. This population is a selected group of cells since only motile cells can pass through cervical mucus and gain initial entry into the female reproductive tract. In animals, some studies indicate that the sperm selected by the reproductive tract and recovered from the uterus and the oviducts have higher fertilization rates but this is not a universal finding. Some species show less discrimination in sperm selection and abnormal sperm do arrive at the oviduct. In contrast, assisted reproductive technologies (ART) utilize a more random sperm population. In this review we contrast the journey of the spermatozoon in vivo and in vitro and discuss this in the context of developing new sperm preparation and selection techniques for ART.

METHODS

A review of the literature examining characteristics of the spermatozoa selected in vivo is compared with recent developments in in vitro selection and preparation methods. Contrasts and similarities are presented.

RESULTS AND CONCLUSIONS

New technologies are being developed to aid in the diagnosis, preparation and selection of spermatozoa in ART. To date progress has been frustrating and these methods have provided variable benefits in improving outcomes after ART. It is more likely that examining the mechanisms enforced by nature will provide valuable information in regard to sperm selection and preparation techniques in vitro. Identifying the properties of those spermatozoa which do reach the oviduct will also be important for the development of more effective tests of semen quality. In this review we examine the value of sperm selection to see how much guidance for ART can be gleaned from the natural selection processes in vivo.

A clinical appraisal of the genetic basis in unexplained male infertility

Unexplained male infertility (UMI), the inability to reproduce despite having a normal sexual history, physical exam and semen analysis, can have a genetic origin. Currently, few diagnostic tools are available for detecting such genetic abnormalities. Karyotyping and fluorescence in situ hybridization (FISH) are respectively used for chromosomal alterations in somatic cells and sperm aneuploidy assessment. Gene sequencing and mutational analysis have been introduced for identifying specific mutations and polymorphisms. Other approaches to the molecular evaluation of spermatozoa are under investigation, including array comparative genomic hybridization and whole-genome sequencing and non-coding ribonucleic acid arrays. Although treating cytogenetic abnormalities and genetic aberrations is still out of reach, the integration of these novel techniques may unravel hidden genetic defects in UMI. Finally, a deeper understanding of the sperm epigenome might allow the development of therapies based on epigenome modifications. This review focuses on the genetic basis of UMI and highlights the current and future methods for the evaluation of genetic defects as they relate to UMI. Review of the literature was carried out using ScienceDirect, OVID, PubMed and MedLine search engines.

Recent insights on the significance of transcriptomic and metabolomic analysis of male factor infertility

Infertility is a worldwide reproductive health problem which affects approximately 15% of couples, with male factor infertility dominating nearly 50% of the affected population. The nature of the phenomenon is underscored by a complex array of transcriptomic, proteomic and metabolic differences which interact in unknown ways. Many causes of male factor infertility are still defined as idiopathic, and most diagnosis tends to be more descriptive rather than specific. As such, the emergence of novel transcriptomic and metabolomic studies may hold the key to more accurately diagnose and treat male factor infertility. This paper provides the most recent evidence underlying the role of transcriptomic and metabolomic analysis in the management of male infertility. A summary of the current knowledge and new discovery of noninvasive, highly sensitive and specific biomarkers which allow the expansion of this area is outlined.

New insights into the expression profile and function of micro-ribonucleic acid in human spermatozoa

OBJECTIVE

To characterize the microRNA (miRNA) expression profile in spermatozoa from human fertile individuals and their implications in human fertility.

DESIGN

The expression levels of 736 miRNAs were evaluated using TaqMan arrays. Ontologic analyses were performed to determine the presence of enriched biological processes among their targets.

SETTING

University research and clinical institutes.

PATIENT(S)

Ten individuals with normal seminogram, standard karyotype, and proven fertility.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Expression levels of 736 miRNAs, presence of enriched metabolic routes among their targets, homogeneity of the population, influence of demographic features in the results, presence of miRNA stable pairs, and best miRNA normalizing candidates.

RESULT(S)

A total of 221 miRNAs were consistently present in all individuals, 452 were only detected in some individuals, and 63 did not appear in any sample. The ontologic analysis of the 2,356 potential targets of the ubiquitous miRNAs showed an enrichment of processes related to cell differentiation, development, morphogenesis, and embryogenesis. None of the miRNAs were significantly correlated with age, semen volume, sperm concentration, motility, or morphology. Correlations between samples were statistically significant, indicating a high homogeneity of the population. A set of 48 miRNA pairs displayed a stable expression, a particular behavior that is discussed in relationship to their usefulness as fertility biomarkers. Hsa-miR-532-5p, hsa-miR-374b-5p, and hsa-miR-564 seemed to be the best normalizing miRNA candidates.

CONCLUSION(S)

Human sperm contain a stable population of miRNAs potentially related to embryogenesis and spermatogenesis.

The presence, role and clinical use of spermatozoal RNAs

BACKGROUND Spermatozoa are highly differentiated, transcriptionally inert cells characterized by a compact nucleus with minimal cytoplasm. Nevertheless they contain a suite of unique RNAs that are delivered to oocyte upon fertilization. They are likely integrated as part of many different processes including genome recognition, consolidation-confrontation, early embryonic development and epigenetic transgenerational inherence. Spermatozoal RNAs also provide a window into the developmental history of each sperm thereby providing biomarkers of fertility and pregnancy outcome which are being intensely studied. METHODS Literature searches were performed to review the majority of spermatozoal RNA studies that described potential functions and clinical applications with emphasis on Next-Generation Sequencing. Human, mouse, bovine and stallion were compared as their distribution and composition of spermatozoal RNAs, using these techniques, have been described. RESULTS Comparisons highlighted the complexity of the population of spermatozoal RNAs that comprises rRNA, mRNA and both large and small non-coding RNAs. RNA-seq analysis has revealed that only a fraction of the larger RNAs retain their structure. While rRNAs are the most abundant and are highly fragmented, ensuring a translationally quiescent state, other RNAs including some mRNAs retain their functional potential, thereby increasing the opportunity for regulatory interactions. Abundant small non-coding RNAs retained in spermatozoa include miRNAs and piRNAs. Some, like miR-34c are essential to the early embryo development required for the first cellular division. Others like the piRNAs are likely part of the genomic dance of confrontation and consolidation. Other non-coding spermatozoal RNAs include transposable elements, annotated lnc-RNAs, intronic retained elements, exonic elements, chromatin-associated RNAs, small-nuclear ILF3/NF30 associated RNAs, quiescent RNAs, mse-tRNAs and YRNAs. Some non-coding RNAs are known to act as epigenetic modifiers, inducing histone modifications and DNA methylation, perhaps playing a role in transgenerational epigenetic inherence. Transcript profiling holds considerable potential for the discovery of fertility biomarkers for both agriculture and human medicine. Comparing the differential RNA profiles of infertile and fertile individuals as well as assessing species similarities, should resolve the regulatory pathways contributing to male factor infertility. CONCLUSIONS Dad delivers a complex population of RNAs to the oocyte at fertilization that likely influences fertilization, embryo development, the phenotype of the offspring and possibly future generations. Development is continuing on the use of spermatozoal RNA profiles as phenotypic markers of male factor status for use as clinical diagnostics of the father's contribution to the birth of a healthy child.