[marchenko]

Men are indeed attracted to relatively wide-hipped women, but there is an upper limit on hip width. There is a biomechanical tradeoff between pelvic shape and locomotor efficiency. The width of the pelvis affects the energy needed for a bipedal gait, since it alters the shape of the largest bones of the lower skeleton and their associated musculature (compare the angle of the femur in men v women and imagine how it affects joint stress). So there's a three way evolutionary arms race between the needs of the large-brained infant, the need to successfully expel said infant, and the need to be able to walk and run efficiently and without musculoskeletal damage.