> In fact, squatting can enlarge the pelvic diameter by at least 2.5cm (1in), while working with gravity makes it far easier to give birth.

Clearly women were meant to give birth while accelerating.

  “Bear down, dear!” I made sure my left foot was positioned for the gravistat control and watched her belly. Big one! As it peaked, I switched from one-quarter gravity up to two gravities almost in one motion—and Llita let out a yip and the baby squirted like a watermelon seed right into my hands. I dragged my foot back to allow the gravistat to put us back on low gee even as I made a nearly instantaneous inspection of the brat. Healthy as a horse. … I slapped his tochis and he bawled. -- Time Enough for Love