Why men have no butt
When any man or woman is socially compelled to continually over-exert, he or she tends to continually stand with wider feet–to feel readier and more balanced.
Also, such a person tends to walk with longer steps–to feel more “effective” or, at least, more busy.
Such unbalanced standing and walking disrupts the balance between hips and legs; this disruption disengages the largest muscle in the body–the buttocks; this disengagement atrophies the largest muscle in the body–the buttocks; this atrophy destroys the balance of the entire lower; this destruction then compounds, destroying the balance of entire body.
So the next time you notice someone with a really nice but–or someone with “no butt”–watch how they stand and walk: those with “no butt” will have wider stances when standing and take longer steps when walking.