Genetics! Which makes me a big case of a huge cosmic joke on me, because by nearly every woman who has seen my dad or his pictures when he was young, even up to his 40s, has described him as hot or very hot. Heck, even my stepdaughter, when she saw a picture of my dad in his early 30s, exclaimed "grandpa is very handsome!". My wife said she had never before complimented on a man's attractiveness. He was a high school science teacher for a long time, his female students were constantly telling me how hot he was. On my FB account, I get friend requests from women asking if I was that hot science teacher they had. I have to tell them no, I'm the ugly son.
Sadly, I inherited none of his good looks, only his genes of longevity.