If the developing individual is a genetic female, the external genitalia differentiate into the female type. The stage of differentiation begins in the 9th week of development. It has been proposed that the estrogens produced by the placenta and fetal ovaries stimulate the development of the external genitalia in the female.
The genital tubercle grows for a short distance and bends inferiorly to form the clitoris. The urethral folds on each side of the urogenital orifice persist as labia minora. The genital swellings enlarge and become the labia ma-jora. The endoderm lined urethral groove forms the vestibule into which the urethra and vagina open.