I don't have kids but if I follow all the men before me from my paternal grandfather's side, if I ever have children I'll probably be in my 30s , my dad was 30 when my brother was born, his dad was like in his late 30s when my uncle was born, my grandfather's dad was pushing 50 when he was born but he was also not the first child and my grandfather's first wife died and he got remarried, but if we go all the way back to my first ancestors with my surname arrived in the Virginia colony in the 1630s he was born in the 1620s, I'm only like the 11th generation back to him in like a 370 year period so most of the men I've descended from on that side were in there 30s or even 40s when their son that I descend from was born.