Yep, just like breast size. Completely controlled by genetics (from the beginning, of course, and if you aren't stuffing your skin with so much fat it starts collecting there, too), but something people who have deliberately turned their bodies into lumpy, misshapen fatsacks just loooove to shame small women for. (While, as you said, claiming their genetics as an excuse for being lumpy, misshapen fatsacks.) They're not just disgusting to look at, they're disgusting inside, too.