Comment by MichaelRo

There's also some wisdom in that if you make kids later in life, you pass them the genes to survive (with 50% probability it seems) up to that age.

So if you're in the kind of family that dies of cancer at 30, and make kids at 25, perspectives don't look great.

Now, not to these people shouldn't make kids but perhaps, choose a spouse whose family dies on average at 60+?

Marry "up", not "down" :)