Evolution is often all-or-nothing --- no one produces "half a child". This is especially true of men, if you believe the 40-80 figure [1]: 40% of men have descendants vs 80% for women. We are the descendants of A) successful people [2] and B) unsuccessful people who took a big gamble (winning the lottery; robbing a bank; crossing the ocean to find better opportunities) that made them wealthy enough to reproduce.
[1] I'm not sure I do.
[2] Obviously - "successful" here basically means "had children". Evolution is a tautology.
Actually people have "half a child" all the time. Every time a sibling reproduces, for example, that's half a child.
So there's a perfectly viable strategy of helping your siblings have more children instead of having more children yourself. If you can create more than 2 successful sibling-children for every child you don't have, your inclusive genetic fitness is increased.
This doesn't mean your conclusion (people gamble! men gamble more than women!) is wrong, but your line of reasoning is.
[1] I'm not sure I do.
[2] Obviously - "successful" here basically means "had children". Evolution is a tautology.