The human vagina is a part of the female body. It is between the perineum and the urethra. Menstrual fluid (red, blood-filled liquid lost during menstruation) leaves the body through the vagina. During sexual intercourse, a penis is put into the vagina. During birth, the vagina opens to let the baby come out from the uterus. The vagina is reddish pink in color, though colors may vary.