Is that why in the past women would marry men 10-20 years older than them? Theoretically the man would be established in a career and have the financial security, and the woman would have the health and energy for childbearing.
I've heard the argument that it's sexist or predatory or whatever, and often people say that 18-20 is still too young physically and carries risks. But if what you're saying is true, then it contradicts that