Surprisingly enough... there is no set rule here. Some people have trouble doing both, others manage both just fine. I would guess there is a correlation between those that really want to achieve both and those that do. Are we going to assume because a few successful people don't have a typical family life that this is because they are successful... and not because they didn't want a typical family life? That seems like a more obvious explanation to me.

So often we look for simple rules as an explanation, but typically outcomes are a result of many smaller factors. It's like the recent discussion here about VC causing more startups to fail vs. succeed. Maybe we can realise that VC isn't the deciding factor, in fact there is likely no single deciding factor, just a bunch of things that impact the outcome.