This document summarizes urogenital development and sex determination in humans. It discusses that in early gestation from 0-7 weeks, the gonads are indifferent, though genetic differences are present. Sex determination begins at fertilization, with XX indicating female and XY male. The presence of SRY on the Y chromosome determines the male phenotype by encoding a protein that functions as a master switch for testis development. Congenital abnormalities that can occur are also described, including Turner's syndrome, true hermaphroditism, pseudohermaphroditism, and testicular feminization.