Boys have trouble being ready for kindergarten and having self discipline. But those that do make it, even though they are fewer, tend to do better than their female counterparts in later life.

Kindergarten activities and society's ideas of self discipline aren't really the conditions human life evolved under. Maybe fighting and looking for action/excitement are the same qualities that make boys successful later (if it doesn't kill or otherwise ruin them first).

Here is my theory (after hours of watching the discovery channel). You don't need many males biologically speaking. So for males, it's do or die from day one. Mostly it's die, but there are a few winners that pass their genes on. Women, as long as they are fertile, don't necessarily enter the same competition... they are the prizes.

Of course civilization doesn't work very well with all the males running around trying to kill each other and breed all the women, so we have laws and religions and kindergartens and diversity training classes. Which kind of puts males (and females maybe to an extent) in a biologically uncomfortable position. Those that succeed in this unnatural environment are those that channel their natural impulses into the pathways society has set up. The poor disadvantaged souls that aren't ready for kindergarten and wind up in prison for violent crimes? Well... they might have been leading the pack 20,000 years ago.