There is a rather fundamental difference in the pelvic structure between males and females. It is readily observable in skeletons. (fleshy differences aside):
Note that the female pelvis has a large circular opening so that little skeletons can be born.
Physicians in Erudin report that during birth, the bones in the pelvis actually dialate. They report that this often seems to cause some 'mild discomfort' on the woman's part, and may explain why they sometimes seem a little impatient with their mates at this point in the delivery.
/shrugs
It's probably just a rumor.
/winks
Message Edited by Mary the Prophetess on 03-21-200608:52 PM