In a recent Medical Hypotheses editorial, I suggested the name psychological neoteny (PN) to refer to the widely-observed phenomenon that adults in modernizing liberal democracies increasingly retain many of the attitudes and behaviors traditionally associated with youth. I further suggested that PN is a useful trait for both individuals and the culture in modernizing societies; because people need to be somewhat child-like in their psychology order to keep learning, developing and adapting to the rapid and accelerating pace of change. Thirdly, I put forward the hypothesis that the major cause of PN in modernizing societies is the prolonged duration of formal education. Here I present a preliminary empirical investigation of this hypothesis of psychological neoteny. Marriage and parenthood are indicative of making a choice to ‘settle down’ and thereby move on from the more flexible lifestyle of youth; and furthermore these are usually commitments which themselves induce a settling down and maturation of attitudes and behaviors. A sevenfold expansion of participation in UK higher education up to 2001 was reflected in delay in marriage and parenthood. Increasing number of years of education is quantitatively the most important predictor of increasing age of the mother at the time of her first birth: among women college graduates about half are aged 30 or older at the time of their first birth – a rise of 400% in 25 years.