ABSTRACT
INTRODUCTION AND SCOPE Excepting some rare and interesting conditions, mammalian offspring generally come in two basic varieties, male and female. The initial gender-determining event occurs at conception as established by the inherited chromosomal constitution. However, the establishment of “genetic sex” at the time of conception is only the first in a complex, highly orchestrated series of events, all of which are necessary to manifest normal male, or female, reproductive function. Other key processes include the determination of “gonadal sex,” whereby the bipotential gonad of a genetic male develops into a testis. While the testis is charged with the all-important task of producing sperm, a network of ducts (e.g., ductus deferens) and secretory organs (e.g., prostate) are also necessary to deliver sperm to the female at the right time, in adequate concentration, and in a condition supportive of subsequent motility and fertilization capacity. The development of these male-specific organs and characteristics is referred to as “phenotypic sex.” To ensure that all of these branches of the male reproductive system function in a coordinated fashion, overall control is managed by the neuroendocrine system, particularly the hypothalamus, pituitary gland, and interstitial cells of the testis.
