I think it's just selection bias for women with fat asses. Baby got back came out in 1992, and remained popular for quite sometime. It puts the people most infl

I think it's just selection bias for women with fat asses. Baby got back came out in 1992, and remained popular for quite sometime. It puts the people most influenced by it right around the age on having first graders. And of course it didn't stand alone, lots of music and popular culture focused much more heavily on ass at that point. Previously almost all focus had been on being skinny with "alert" breasts.