Science

This is anecdotal but as someone that returned to college in my late 20s the women are just so much more mature than the men are.

My female classmates will be consistently in class, maintaining good GPAs, and often working part time while participating in clubs or lab programs.

The men are well struggling to shower and bragging about not showing up to class thinking it makes them look cool and just being icky in general.

As my female friends put it the bar is in hell and they still aren't getting over it.

The most intuitive answer would be synthesizing the common anthropological claim that early division of labor meant men did risky tasks while women did safer tasks that were more compatible with childcare (I was taught this was 100% always true and real when I took anthropology in college, but I believe more recent research has basically concluded that it's a general trend but not as hard a rule as earlier anthropologists claimed), which would mean a bias towards men dying young in general with survivors either taking fewer risks or having the experience to better manage and react to them, while women would have a constant ongoing risk from potential pregnancy complications meaning they have an increasing probability of early death the more times they get pregnant.

So you get surviving men being more likely to keep reproducing with women who are either dying sooner or later from pregnancy complications or who quickly stop having kids to focus on childcare and not going through such constant strain and risk, leaving the same cycle to repeat with the same man and a new woman.

And that's before you start speculating about status, hierarchy, violent competition, etc which you literally just can't do for early humans because there is no source of data for that sort of thing: modern hunter/gatherer cultures were long treated as some sort of preserved window into the past, but they're fundamentally not because not only are they cultures that have been developing for a further tens of thousands to hundreds of thousands of years after whatever point you want to speculate on, they also haven't been existing in some sort of isolated preservation environment and instead have lived alongside horticultural* and agricultural societies with varying degrees of contact and conflict. They can even be offshoots of those civilizations who simply started surviving on the margins as they could.

* Horticultural civilizations have also been treated this way by anthropologists, but that's also not valid for the same reason: they are matured civilizations that just lacked specific technologies, they aren't windows into the past and in many cases they were still existing alongside and having contact with agricultural civilizations. Hell, western chauvinism runs so deep that even agricultural and pastoralist civilizations in the Americas, Africa, and Asia got treated in that same way, when all they lacked compared to Europeans were specific metallurgic and machining technologies that were still comparatively brand new.