A: Sagittal section of p63+/− newborn mouse revealing normal bladder (b), clitoral (cl), uterine (u), and urethral (ur) development. The vaginal introitus (i) is distinct from the anus (a). B: p63-null mouse with absent skin, clitoral hypoplasia, and absence of perineal rectovaginal septation with a common cloacal (clo) opening.