The pelvis of Sts 14 (Australopithecus africanus) was reconstructed through mirror-image moulding. A comparison with the pelvic reconstructions of AL288-1 ("Lucy"; A. ?afarensis) of Lovejoy (1979), Schmid (1983) and a preliminary reconstruction by the first author revealed marked differences between Sts 14 and AL 288-1 which are unlikely to be explained by different methods of reconstruction. A re-examination of sexual characteristics together with an analysis of the birth mechanism led to the conclusion that the morphologically different birth canals of Sts 14 and AL288-1 could be interpreted as reflecting sexual dimorphism in small-bodied gracile australopithecines.