It makes perfect sense. Big butt means bigger pelvis. This is inherited from her mother. Bigger pelvis means more room for a developed head to pass through. Bigger head, bigger brain equals smarter although it is politically incorrect to say so.
I also think that the increasing use of cesarean section will mess with natural selection which would make bigger pelvis a survival advantage. Once we decouple the pelvis size from the need to fit through it we will cause a great deal of pain in the future when it becomes too expensive under socialized medicine. Big heads won’t squeeze through and smarter babies will die. Cesarean birth selects for smaller pelvis size on average.
Nope—zero evidence of that at all.
In fact, it works to the contrary.