Why boys will be boys and girls will be girls: Human sex development and its defects

Transvaginal three-dimensional ultrasound assessment of embryonic genital tubercle at 8-10+6 weeks of gestation

OBJECTIVES

To assess embryonic genital tubercle using transvaginal three-dimensional (3D) ultrasound at 8-10+6 weeks of gestation.

METHODS

One-hundred and two transvaginal 3D ultrasound scans were performed for first-trimester dating at 8-10+6 weeks of gestation. The genital tubercle angle (GTA) and genital tubercle length (GTL) were measured with a mid-sagittal view of the embryo using the 3D ultrasound multiplanar mode. Intra- and inter-observer agreements regarding GTA and GTL were also assessed with Bland-Altman plots and intra- and inter-correlation coefficients.

RESULTS

There were no significant differences in GTA between male and female embryos at 8, 9, 10 weeks, or 8-10+6 weeks of gestation, respectively. There were also no significant differences in GTL between male and female embryos at 8, 9, 10 weeks, or 8-10+6 weeks of gestation, respectively. However, GTL increased linearly with advancing gestation (r=0.8276, p<0.00001). Mean GTL (SD) values at 8, 9, and 10 weeks were 0.833 mm (0.274), 1.623 mm (0.262), and 2.152 mm (0.420), respectively (p<0.001). Intra- and inter-reproducibilities of GTA and GTL were excellent. The intra- and inter-correlation coefficients of GTA and GTL were 0.964 and 0.995, and 0.996 and 0.9933, respectively.

CONCLUSIONS

The genital tubercle could be identified using transvaginal 3D ultrasound at 8-10+6 weeks of gestation. However, sex differentiation could not be performed at this age. The genital tubercle linearly developed with advancing gestation during the mid-first trimester of pregnancy.

The Development of Normal Fetal External Genitalia Throughout Gestation

In this review, we describe normal development of fetal genitalia throughout gestation as well as the identification of normal male and female genitalia on ultrasound. We use abnormal and ambiguous genitalia as illustrative tools to assist with the identification of normal genitalia and recognition of some of the most common abnormalities in external genitalia development.

A Common Path: Magnetic Resonance Imaging of Müllerian and Wolffian Duct Anomalies

PURPOSE OF REVIEW

This review summarizes the pathway of Mullerian and Wolffian duct development, anomalies that result from disruptions to this pathway, and the characteristics on advanced imaging that identify them.

RECENT FINDINGS

In-office evaluation for reproductive anomalies is usually inadequate for the diagnosis of congenital reproductive anomalies. Magnetic resonance imaging (MRI) has usurped invasive diagnostic methods including laparoscopy, hysteroscopy, and vasography as the new gold standard. Because of its superior soft-tissue delineation and the availability of advanced functional sequences, MRI offers a sophisticated method of distinguishing reproductive anomalies from one another, characterizing the degree of defect severity, and evaluating for concomitant urogenital anomalies non-invasively and without radiation exposure to the patient. Congenital anomalies of the Mullerian and Wolffian duct can be incredibly nuanced, requiring prompt and accurate diagnosis for management of infertility. Definitive diagnosis should be made early with MRI.

Temporal sociomedical approaches to intersex* bodies

The history of the field of intersex bodies/bodies with variations of sex development (VSD) reflects the ongoing tension between sociomedical attempts to control uncertainty and reduce the duration of corporeal uncertainty by means of early diagnosis and treatment, and the embodied subjects who resist or challenge these attempts, which ultimately increase uncertainty. Based on various qualitative studies in the field of intersex, this article describes three temporal sociomedical approaches that have evolved over the last decade and aims to address the uncertainty surrounding intersex/VSD bodies. These approaches are (1) the corrective-concealing approach, which includes early surgeries and hormone therapies intended to "correct" intersex conditions and the deliberate concealment of the ambiguity and uncertainty associated with intersex conditions; (2) the preventive approach, which involves early genetic diagnostic methods aimed at regulating or preventing the recurrence of hereditary conditions under the umbrella of VSD; and (3) the wait-and-see approach, which perceives intersex bodies as natural variations and encourages parents to take time, wait, and give their children the right to bodily autonomy. A comparison of these approaches from biopolitical, phenomenological, and pragmatic perspectives reveals that time is an essential social agent in addressing and controlling uncertainty, a gatekeeper of social norms and social and physical orders, and, on the other hand, a sociopolitical agent that enables creative social change.

Considering Sex as a Biological Variable in Basic and Clinical Studies: An Endocrine Society Scientific Statement

In May 2014, the National Institutes of Health (NIH) stated its intent to "require applicants to consider sex as a biological variable (SABV) in the design and analysis of NIH-funded research involving animals and cells." Since then, proposed research plans that include animals routinely state that both sexes/genders will be used; however, in many instances, researchers and reviewers are at a loss about the issue of sex differences. Moreover, the terms sex and gender are used interchangeably by many researchers, further complicating the issue. In addition, the sex or gender of the researcher might influence study outcomes, especially those concerning behavioral studies, in both animals and humans. The act of observation may change the outcome (the "observer effect") and any experimental manipulation, no matter how well-controlled, is subject to it. This is nowhere more applicable than in physiology and behavior. The sex of established cultured cell lines is another issue, in addition to aneuploidy; chromosomal numbers can change as cells are passaged. Additionally, culture medium contains steroids, growth hormone, and insulin that might influence expression of various genes. These issues often are not taken into account, determined, or even considered. Issues pertaining to the "sex" of cultured cells are beyond the scope of this Statement. However, we will discuss the factors that influence sex and gender in both basic research (that using animal models) and clinical research (that involving human subjects), as well as in some areas of science where sex differences are routinely studied. Sex differences in baseline physiology and associated mechanisms form the foundation for understanding sex differences in diseases pathology, treatments, and outcomes. The purpose of this Statement is to highlight lessons learned, caveats, and what to consider when evaluating data pertaining to sex differences, using 3 areas of research as examples; it is not intended to serve as a guideline for research design.

The Neonate with Ambiguous Genitalia

Neonates with ambiguous genitalia have various clinical presentations, etiologies, and outcomes, ranging from benign to life-threatening. This review provides a summary of these findings. Some diagnoses may lead to delayed sex assignment. A systematic approach to the evaluation of disorders of sex development can allow for timely treatment and family counseling.

Disorders of Sex Development: Classification, Review, and Impact on Fertility

In this review, the elements included in both sex determination and sex differentiation are briefly analyzed, exposing the pathophysiological and clinical classification of disorders or anomalies of sex development. Anomalies in sex determination without sex ambiguity include gonadal dysgenesis, polysomies, male XX, and Klinefelter syndrome (dysgenesis and polysomies with a female phenotype; and sex reversal and Klinefelter with a male phenotype). Other infertility situations could also be included here as minor degrees of dysgenesis. Anomalies in sex determination with sex ambiguity should (usually) include testicular dysgenesis and ovotesticular disorders. Among the anomalies in sex differentiation, we include: (1) males with androgen deficiency (MAD) that correspond to those individuals whose karyotype and gonads are male (XY and testes), but the phenotype can be female due to different hormonal abnormalities. (2) females with androgen excess (FAE); these patients have ovaries and a 46,XX karyotype, but present varying degrees of external genital virilization as a result of an enzyme abnormality that affects adrenal steroid biosynthesis and leads to congenital adrenal hyperplasia; less frequently, this can be caused by iatrogenia or tumors. (3) Kallman syndrome. All of these anomalies are reviewed and analyzed herein, as well as related fertility problems.

Diagnosis and treatment of the intra-abdominal gonad in the pediatric population: Testes, ovaries, dysgenetic gonads, streaks, and ovotestes

BACKGROUND/PURPOSE

Pediatric surgical specialists are often confronted with the difficult task of identifying, diagnosing and managing intra-abdominal gonads in children. Ranging from the intra-abdominal cryptorchid testis to normal or pathologic ovaries and gonads in disorders of sexual development, all intra-abdominal gonads in the pediatric population pose different diagnosis and management challenges. Understanding the hormonal and fertility potential of the gonad and knowing its potential cancer risk is essential when deciding how to manage these patients. In addition, the ideal surgical management for each one of these patients is often debated.

METHODS

Descriptive literature review.

RESULTS/CONCLUSION

Herein, we reviewed gonadal formation, common etiologies, diagnosis and management of intra-abdominal testes, pathologic ovaries and gonads in disorders of sexual development. Fertility potential and cancer risk for each were also reviewed and how both affect surgical management of the gonad.

TYPE OF STUDY/LEVEL OF EVIDENCE

Review Article, Level V.

Deficiencies in Scientific Evidence for Medical Management of Gender Dysphoria

Individuals who experience a gender identity that is discordant with biological sex are increasingly presenting to physicians for assistance in alleviating associated psychological distress. In contrast to prior efforts to identify and primarily address underlying psychiatric contributors to gender dysphoria, interventions that include uncritical social affirmation, use of gonadotropin-releasing hormone agonists to suppress normally timed puberty, and administration of cross-sex steroid hormones to induce desired secondary sex characteristics are now advocated by an emerging cohort of transgender medicine specialists. For patients with persistent gender dysphoria, surgery is offered to alter the appearance of breasts and genital organs. Efforts to address ethical concerns regarding this contentious treatment paradigm are dependent upon reliable evidence on immediate and long-term risks and benefits. Although strong recommendations have been made for invasive and potentially irreversible interventions, high-quality scientific data on the effects of this approach are generally lacking. Limitations of the existing transgender literature include general lack of randomized prospective trial design, small sample size, recruitment bias, short study duration, high subject dropout rates, and reliance on "expert" opinion. Existing data reveal significant intervention-associated morbidity and raise serious concern that the primary goal of suicide prevention is not achieved. In addition to substantial moral questions, adherence to established principles of evidence-based medicine necessitates a high degree of caution in accepting gender-affirming medical interventions as a preferred treatment approach. Continued consideration and rigorous investigation of alternate approaches to alleviating suffering in people with gender dysphoria are warranted.

SUMMARY

This paper provides an overview of what is currently known about people who experience a gender identity that differs from their biological sex and the associated desire to engage the medical profession in alleviating associated discomfort and distress. The scientific evidence used to support current recommendations for affirming one's preferred gender, halting normally timed puberty, administering cross-sex hormones, and surgically altering primary and secondary sexual traits are summarized and critically evaluated. Serious deficits in understanding the cause of this condition, the reasons for the marked increase in people presenting for medical care, together with immediate and long-term risks relative to benefit of medical intervention are exposed.

Pluripotent Cell Models for Gonadal Research

Sex development is a complex process involving many genes and hormones. Defects in this process lead to Differences of Sex Development (DSD), a group of heterogeneous conditions not as rare as previously thought. Part of the obstacles in proper management of these patients is due to an incomplete understanding of the genetics programs and molecular pathways involved in sex development and DSD. Several challenges delay progress and the lack of a proper model system for the single patient severely hinders advances in understanding these diseases. The revolutionary techniques of cellular reprogramming and guided in vitro differentiation allow us now to exploit the versatility of induced pluripotent stem cells to create alternatives models for DSD, ideally on a patient-specific personalized basis.

Genome-wide analysis of ETV1 targets: Insights into the role of ETV1 in tumor progression

ETS variant 1 (ETV1) is a key player in metastatic progression in several types of human cancers, yet the direct target genes of ETV1 and the mechanisms by which ETV1 exerts its deleterious function remain largely elusive. Here, we performed large-scale mapping and analysis of target loci of ETV1 in the prostate cancer cells LNCaP using the DNA adenine methyltransferase identification technique, we identified close to 800 direct targets for ETV1. Expression analysis using quantitative reverse transcription polymerase chain reaction confirmed a positive regulation by ETV1 in most of the genes examined. Furthermore, gene and pathway analysis unraveled new signaling pathways and biological networks that interact with ETV1. Our findings cast light on genes and networks regulated by ETV1, it also opens new fronts for studying the role of ETV1 and its target genes in tumorigenesis.

A Human Gonadal Cell Model From Induced Pluripotent Stem Cells

Sertoli cells are main players in the male gonads development and their study may shed light on 46,XY disorders of sex development (DSD). Mature primary Sertoli cells are incapable of proliferating in prolonged in vitro cultures and the available Sertoli cell models have several limitations since they derive from mouse or human cancer tissues. We differentiated human fibroblasts (HFs)-derived induced pluripotent stem cells into Sertoli-like cells (SLC) and, in order to characterize this new Sertoli cell model, we performed gene expression analyses by NextGeneration Sequencing techniques. This approach revealed that our putative SLC have reduced expression of pluripotency markers and expressed Sertoli cell markers such as SRY-Related HMG-Box 9 (SOX9), vimentin (VIM), and claudin-11 (CLDN-11). More in detail, the transcriptional profile analysis suggested that these cells are in an early stage of Sertoli cells maturation. Harnessing the power of induced pluripotent stem cells, we were able to generate SLC that show genetic and functional similarities to human Sertoli cells (HSerCs). SLC could become an excellent source of patient-specific Sertoli cells that could be of paramount benefit for both basic research and personalized medicine in sex development and reproductive medicine.

A boy with 46,X,+mar presenting gynecomastia and short stature

A 15-year-old boy was referred due to gynecomastia and short stature. He was overweight and showed the knuckle-dimple sign on the left hand, a short fourth toe on the left foot, and male external genitalia with a small phallus. His levels of estradiol and follicle-stimulating hormone were increased, and his testosterone concentration was normal. Other hormonal tests were within the normal range. Radiographs showed short fourth and fifth metacarpals and fourth metatarsal bones. The karyotype was reported as 46,X,+mar, and the marker chromosome was shown to originate from the Y chromosome, which was identified by fluorescence in situ hybridization. Polymerase chain reaction and direct sequencing were used to clarify the deleted loci of the Y chromosome by making use of Y-specific sequence-tagged sites (STSs). The sex-determining region Y and centromere were verified, and there were microdeletions on the long arm of the Y chromosome. The azoospermia factor (AZF) b region was partially deleted, and AZFa and AZFc were completely deleted. Two STS probes of sY143 and the Y chromosome RNA recognition motif in AZFb showed positive signals corresponding to Yq11.223. The karyotype of the patient was interpreted as 46,X,der(Y)del(Y)(q11.21q11.222)del(Y)(q11.23qter). Herein, we report a rare case of a boy presenting with gynecomastia and short stature with 46, X, +mar, which originated from the Y chromosome, which was identified to have Yq microdeletions.

Neonatal Sex Assignment in Disorders of Sex Development: A Philosophical Introspection

Management of ambiguous genitalia is highly controversial. This condition was known previously as intersex and presently as disorders of sex development (DSD). There is no consensus regarding the choice, timing and method of sex assignment in neonates with DSD. Consensus conferences could not unify the views of various stakeholders and third parties. This article philosophically examines the nature and origin of such controversies. Misconception, bias and conflicting priorities are identified as the three cardinal sources of controversies. Conceptual duality of sexes, confused notion of sex and gender, bias towards penetrative intercourse, conflict between utopian ideals and reality, unwillingness to compromise are identified as perpetuators of controversies. Suggestions are made regarding sex assignment in various types of DSD based on the understanding of published literature and the author's personal experience.