Once they get a girl, they don't need to struggle.
In every society in history, risk-taking behavior (criminal and creative)
- rapidly increases in early adolescence
- peaks in early adulthood
- rapidly decreases through the 20s and 30s
- levels off in middle age
And, the reason is simple. Chicks. "Men have built and destroyed civilizations in order to impress women."
However, once men have children they spend their time caring for them and their tendency toward crime and creative work wanes.
After the birth of their first child men simply do not feel like acting violently, stealing, or conducting additional scientific experiments. They just want to settle down after the birth of their child but they do not know exactly why.
Female productivity, on the other hand, is not equally influenced by age and does not reach the same peaks and lows.