I don't have kids, but it's pretty clear they take ALL of the time. But raising kids is far more valuable & rewarding (if you do it well) than most of the activities people might do instead.
"But I really like drinking with my friends & going to the movies" ...okay, well when you're 80 and lonely because all of your friends are dead or dying are you really gonna be glad that you partied instead of raising a family that would still want to see you & actually make your life seem like it was worth something?
It's definitely a low time preference investment, but there are few, if any, better choices.