Theory #2 of why Brad has no Ass: That crazy thing we call genetics.

If you come from a lineage of "explosive asses" you too will be blessed with a bubble of a bum. Conversly, if you come from a lineage of no asses you will be horribly scarred and taunted by your friends for your lack of ass.

This theory is backed by the fact that my grandfather, father nor my brother have an ass, no matter how much my brother tries to contest this. My mother also lacks and ass but the jury is out to as whether it is a sagging ass or a flat ass. The former not being her fault, but that of our cruel friend gravity.