Comment by glitchc

This is the danger of anecdotes, they can lead to bias. I have a PhD and I had my first child at 28. Almost all of my colleagues have families and children, except for the one person who was unable to attract a suitable mate (and not for lack of trying). Sometimes very bright people have trouble attracting an equivalent person. The pool is that much smaller and other factors (socioeconomic, culture) still play a role as per other relationships.