Here is an excerpt from Satoshi Kanazawa's book "Why Beautiful People Have More Daughters" regarding effect of marriage on men's (scientists in this case) productivity/creativity;

 

A comparison of the “age-genius curve” among scientists who were married at some point in their lives with the same curve among those who never married shows the strong desistance effect of marriage on scientific productivity. Half as many (50.0 percent) unmarried scientists make their greatest contributions in their late 50s as they do in their late 20s. The corresponding percentage among the married scientists is 4.2 percent. The mean age of peak productivity among the unmarried scientists (39.9) is significantly later than the mean peak age among married scientists (33.9).

Given that the Nobel Prize for scientific achievement didn’t exist in the ancestral environment, the evolved psychological mechanisms of men appear to be rather precisely tuned to marriage as a cue to desistance. Nearly a quarter (23.4 percent) of all married scientists make their greatest scientific contribution in their career and then desist within five years after their marriage. The mean delay (the difference between their marriage and their peak productivity) is a mere 2.6 years; the median is 3.0 years. It therefore appears that scientists rather quickly desist after marriage, while unmarried scientists continue to do important scientific work. When you remember that great scientific discoveries usually require many years of cumulative and continued research, the near coincidence of the male scientists’ marriages and their desistance (after which they cease to make any greater scientific discoveries) is remarkable. A study by the sociologists Lowell L. Hargens, James C. McCann, and Barbara F. Reskin also demonstrates that childless research chemists are more productive than those with children.

You may think that unmarried scientists continue to make scientific contributions much later in their lives because they have more time to devote to their careers. Unmarried and therefore childless scientists do not have to spend time taking care of their children, driving them back and forth between soccer practices and ballet lessons, or doing half the house hold chores, and that is why unmarried scientists can continue making great contributions to science while married scientists must desist to devote their time to their families. This is precisely Hargens et al.’s interpretation of the negative correlation between parenthood and productivity among research chemists.