A genital tubercle
is a body of tissue present in the development of the urinary and reproductive organs
. It forms in the ventral, caudal region of mammalian embryos
of both sexes
, and eventually develops into a phallus
. In the human fetus
the genital tubercle develops around week 4 of gestation
, and by week 9 becomes recognizably either a clitoris
Even after the phallus is developed, the term genital tubercle remains, but only as the terminal end of it, which develops into either the glans penis or the glans clitoridis.
The genital tubercle is sensitive to dihydrotestosterone and rich in 5-alpha-reductase, so that the amount of fetal testosterone present after the second month is a major determinant of phallus size at birth.