More intelligent women are less likely to choose to have children, research suggests.
http://personal.lse.ac.uk/kanazawa/pdfs/SSR2014.pdfAbstract
Demographers debate why people have children in advanced industrial societies where
children are net economic costs. From an evolutionary perspective, however, the important
question is why some individuals choose not to have children. Recent theoretical developments
in evolutionary psychology suggest that more intelligent individuals may be more
likely to prefer to remain childless than less intelligent individuals. Analyses of the
National Child Development Study show that more intelligent men and women express
preference to remain childless early in their reproductive careers, but only more intelligent
women (not more intelligent men) are more likely to remain childless by the end of their
reproductive careers. Controlling for education and earnings does not at all attenuate the
association between childhood general intelligence and lifetime childlessness among
women. One-standard-deviation increase in childhood general intelligence (15 IQ points)
decreases women’s odds of parenthood by 21–25%. Because women have a greater impact
on the average intelligence of future generations, the dysgenic fertility among women is
predicted to lead to a decline in the average intelligence of the population in advanced
industrial nations
Vasectomy isn't a best way for 'intelligent men' I guess. They just postpone their desire to have children in their reproductive careers. E.g Bill Gates, he married in 1994, or when he was being 39 yo.