part of multi-tissue structure reproductive structure undifferentiated genital tubercle genital swelling EMAPA:30074 labioscrotal swelling Wikipedia:Labioscrotal_swelling EMAPA:35377 VHOG:0000976 tuberculum labioscrotale Paired structures in the embryo that represent the final stage of development of the caudal end of the external genitals before sexual differentiation. In both males and females the two swellings merge: in the female, they become the posterior labial commissure; In the male, they become the scrotum.