There's a movie or two about that.
That's Mother Nature trying to kill you off ..... slow you down a step for the dire wolves and sabre-toothed cats.
Ever notice that that slowdown age, 28, just happens to be about double the age of puberty?
As soon as your firstborn is ready to drop kids of her own and sire kids of his own, Mother Nature's genetic casino doesn't need your ass around any more -- to the wolves with you!!
Croupier, please escort the old, used-up, 30-year-old fat guy to the door. Thanks for playing, sir, and have a nice blood poisoning.
There's a movie or two about that.
Never thought about it that way.
Makes sense to me.