Testis Development and Descent

Abstract

Fetal development of reproductive system is a complex process which can be divided in two main stages: sex determination and sexual differentiation. During sex determination, the bipotential gonadal primordium develops – according to chromosomal sex – into either testis or ovary. Sexual differentiation subsequently involves fetal gonadal production of peptide and steroid hormones that are responsible for male or female phenotype. This process occurs during a brief window of time and is based on sex-specific expression of transcription factors and signaling molecules that in turn drive cell fate commitment by regulating migration, proliferation, and patterning of somatic and germ cells into testis and ovary. Pathway to maleness relies on mechanisms that have recently been shown to both promote testis development and simultaneously antagonize ovarian fate. Our understanding of these pathways has grown over the past few years, and novel players involved in sexual development, such as epigenetic regulators, have arisen. Enlightenment of these networks is critical for a better characterization of conditions such as disorders of sex development (DSD), infertility, and gonadal cancer.