The breakdown of AAT is that our ancestors became human, lost most of our body hair (while getting a big mane on our scalps), got bigger brains, moved our genitalia (and increased the size), etc, just because some moistened binks stood around in the surf. :’) “The Descent of Woman” shook up a lot of people because it was such a then-trendy, faddish, blatantly political work passed off as a scientific theory. The most plausible parts of it, IMHO, are how she ridicules what were then the conventional explanations for various anatomical characteristics. :’)
Sorry, couldn't resist -- link only.
Cheers!