In mammals, gonadal somatic cell lineage differentiation determines the development of the bipotential gonad into either the ovary or testis. Sertoli cells, the only somatic cells in the spermatogenic tubules, support spermatogenesis during gonadal development. During embryonic Sertoli cell lineage differentiation, relevant genes, including WT1, GATA4, SRY, SOX9, AMH, PTGDS, SF1, and DMRT1, are expressed at specific times and in specific locations to ensure the correct differentiation of the embryo toward the male phenotype. The dysregulated development of Sertoli cells leads to gonadal malformations and male fertility disorders. Nevertheless, the molecular pathways underlying the embryonic origin of Sertoli cells remain elusive. By reviewing recent advances in research on embryonic Sertoli cell genesis and its key regulators, this review provides novel insights into sex determination in male mammals as well as the molecular mechanisms underlying the genealogical differentiation of Sertoli cells in the male reproductive ridge.

BACKGROUND: Aphallia is a rare congenital anomaly often associated with other urogenital anomalies. The management of aphallia cases for both the immediate and long-term treatment of patients with aphallia pose a major dilemma. Patients are at risk for psychosocial and psychosexual challenges throughout life.
METHODS: A systematic review was conducted on aphallia cases. We searched online databases until March 2023 for relevant articles and performed according to the PRISMA-P guidelines.
RESULTS: Of the 43 articles screened, there were 33 articles included. A total of 41 patients were analyzed qualitatively. Asia is the region with the most aphallia cases with 53% (n:22), while the United States is the country with the most most reported aphallia cases 31% (n:13). Most cases were identified as male sex (n: 40), and most cases were neonate with 68% (n:28) cases. Physical examination generally found 85% (N = 35) with normal scrotal development and palpable testes. The most affected system with anomalies is the genitourinary system with fistulas in 80% (n:29) cases. Initial management in 39% (n:16) of patients involved vesicostomy. Further management of 31% (n:13) included phalloplasty or penile reconstruction, and 12% (n:5) chose female sex. 17% (n:7) of patients refused medical treatment or were lost to follow-up, and 12% (n = 5) patients deceased.
CONCLUSIONS: Aphallia is a rare condition and is often associated with other inherited genitourinary disorders. In most cases, physical examinations are normal except for the absence of a phallus, and laboratory testing shows normal results. The initial management typically involves the vesicostomy procedure. Subsequent management focuses on gender determination. Currently, male sex is preferred over female. Due to the significant variability, the rarity of cases, and the lack of long-term effect reporting in many studies on aphallia, further research is needed to minimize bias.

Müllerian ducts are paired embryonic tubes that give rise to the female reproductive tract. In humans, the Müllerian ducts differentiate into the Fallopian tubes, uterus and upper portion of the vagina. In birds and reptiles, the Müllerian ducts develop into homologous structures, the oviducts. The genetic and hormonal regulation of duct development is a model for understanding sexual differentiation. In males, the ducts typically undergo regression during embryonic life, under the influence of testis-derived Anti-Müllerian Hormone, AMH. In females, a lack of AMH during embryogenesis allows the ducts to differentiate into the female reproductive tract. In the chicken embryo, a long-standing model for development and sexual differentiation, Müllerian duct development in females in asymmetric. Only the left duct forms an oviduct, coincident with ovary formation only on the left side of the body. The right duct, together with the right gonad, becomes vestigial. The mechanism of this avian asymmetry has never been fully resolved, but is thought to involve local interplay between AMH and sex steroid hormones. This mini-review re-visits the topic, highlighting questions in the field and proposing a testable model for asymmetric duct development. We argue that current molecular and imaging techniques will shed new light on this curious asymmetry. Information on asymmetric duct development in the chicken model will inform our understanding of sexual differentiation in vertebrates more broadly.

Sex determination in forensic dentistry is a major step towards postmortem profiling. The most widely recognized method is DNA, yet its application in the dental field of forensic sciences is still impractical. Depending on the conditions of the remains, teeth are often the only surviving organ. Some systematic reviews (SRs) have been recently produced; hence this umbrella review critically assesses their level of evidence and provides an overall comprehensive view. An electronic database search was conducted in four databases (PubMed, Cochrane, Web of Science, and LILACS) and three grey search engines up to December 2021, focusing on SRs of sex determination through forensic dentistry procedures. The methodological quality of the SRs was analyzed using the measurement tool to assess SRs criteria (AMSTAR2). Five SRs were included, two of critically low quality and three of low quality. The SRs posited that canines are the most dimorphic teeth; oral tissue remnants are a rich source for sex determination by DNA tracing; and artificial intelligence tools demonstrate high potential in forensic dentistry. The quality of evidence on sex determination using dental approaches was rated as low. Well-designed clinical trials and high standard systematic reviews are essential to corroborate the accuracy of the different procedures of sex determination in forensic dentistry.

Triggers and biological processes controlling male or female gonadal differentiation vary in vertebrates, with sex determination (SD) governed by environmental factors or simple to complex genetic mechanisms that evolved repeatedly and independently in various groups. Here, we review sex evolution across major clades of vertebrates with information on SD, sexual development and reproductive modes. We offer an up-to-date review of divergence times, species diversity, genomic resources, genome size, occurrence and nature of polyploids, SD systems, sex chromosomes, SD genes, dosage compensation and sex-biased gene expression. Advances in sequencing technologies now enable us to study the evolution of SD at broader evolutionary scales, and we now hope to pursue a sexomics integrative research initiative across vertebrates. The vertebrate sexome comprises interdisciplinary and integrated information on sexual differentiation, development and reproduction at all biological levels, from genomes, transcriptomes and proteomes, to the organs involved in sexual and sex-specific processes, including gonads, secondary sex organs and those with transcriptional sex-bias. The sexome also includes ontogenetic and behavioural aspects of sexual differentiation, including malfunction and impairment of SD, sexual differentiation and fertility. Starting from data generated by high-throughput approaches, we encourage others to contribute expertise to building understanding of the sexomes of many key vertebrate species. This article is part of the theme issue \'Challenging the paradigm in sex chromosome evolution: empirical and theoretical insights with a focus on vertebrates (Part I)\'.

Forensic odontology is the application of dental principles to legal issues. It is an investigative aspect of dentistry that analyzes dental evidence for human identification. Sex determination is a subdivision of forensic odontology, and it is important especially when information relating to the deceased is unavailable. Sex determination becomes the first priority in the process of identification of a person by a forensic investigator in the case of mishaps, chemical and nuclear bomb explosions, natural disasters, crime investigations, and ethnic studies. Determination of sex/gender using skeletal remains presents a great problem to forensic experts, especially when only fragments of body are recovered. Forensic odontologist can assist other experts to determine the sex of the remains using teeth and skull traits. Various features of teeth such as morphology, crown size, and root length are characteristics for male and female sexes. There are also differences in the skull pattern and skull traits of two sexes. These will help forensic odontologists to identify the sex of the remains. The library dissertation contents and several articles and books were electronically searched in Google using the keywords \"sex determination,\" \"forensic dentistry,\" \"sex determination in forensic dentistry.\" The contents were screened between 1950 and 2015 by going through the title and abstracts and full-text reading. The purpose of this article is to familiarize the different methods of sex determination.

A number of dioecious species are grown across India and some of those plants play a crucial role in the agro-based economy of the country. The diagnosis of sex is very difficult in the dioecious plant prior flowering wherein sex identification at the seedling stage is of great importance to breeders as well as farmers for crop improvement or production purpose. A comprehensive approach of sex determination comprising morphological, biochemical, cytological and molecular attributes is a must required for gender differentiation in dioecious plant species. In the present review, we highlighted the economical, medicinal as well as industrial importance of most of the dioecious species extensively grown in Indian subcontinent. In addition to that, the cytogenetic, genetic as well as molecular information in connection to their sex determination were critically discussed in this review.

Forensic odontology is the application of dental principles to legal issues. Sex determination is a subdivision of forensic odontology and it is very important especially when information relating to the deceased is unavailable. Sex determination becomes the first priority in the process of identification of a person by a forensic investigator in the case of mishaps, chemical and nuclear bomb explosions, natural disasters crime investigations, and ethnic studies. This article reviews upon the various methods used in sex determination.

Sex determination of domestic animal\'s meat is of potential value in meat authentication and quality control studies. Methods aiming at determining the sex origin of meat may be based either on the analysis of hormone or on the analysis of nucleic acids. At the present time, sex determination of meat and meat products based on hormone analysis employ gas chromatography-mass spectrometry (GC-MS), high-performance liquid chromatography-mass spectrometry/mass spectrometry (HPLC-MS/MS), and enzyme-linked immunosorbent assay (ELISA). Most of the hormone-based methods proved to be highly specific and sensitive but were not performed on a regular basis for meat sexing due to the technical limitations or the expensive equipments required. On the other hand, the most common methodology to determine the sex of meat is unquestionably traditional polymerase chain reaction (PCR) that involves gel electrophoresis of DNA amplicons. This review is intended to provide an overview of the DNA-based methods for sex determination of meat and meat products.

The general perspective of ovary organogenesis is that the ovary is the default organ which develops in the absence of testis-promoting factors. Testis formation, on the other hand, is a male-specific event promoted by active components that override the default ovarian process. However, when comparing the sex determination mechanism among different vertebrate species, it is apparent that this default view of ovary formation can only be applied to mammals. In species such as reptiles and birds, ovary formation is an active process stimulated by estrogen. Remnants of this estrogen-dominant pathway are still present in marsupials, a close relative of eutherian mammals, like humans and mice. Although initial formation of the mammalian ovary has become strictly regulated by genetic components and is therefore independent of estrogen, the feminizing effect of estrogen regains its command in adult ovaries. When estrogen production, or its signaling, is inhibited, transdifferentiation of ovarian tissues to testis structures occur in adult females. Taken together, these observations prompt us to reconsider the process of ovary organogenesis as the default organ and question if testis development is actually the default pathway.