That’s not an ad hominem attack.  That’s what a couple of sociologists found out:

In the 1960s Jack Block and his wife and fellow professor Jeanne Block (now deceased) began tracking more than 100 nursery school kids as part of a general study of personality. The kids’ personalities were rated at the time by teachers and assistants who had known them for months. There’s no reason to think political bias skewed the ratings — the investigators were not looking at political orientation back then. Even if they had been, it’s unlikely that 3- and 4-year-olds would have had much idea about their political leanings.

A few decades later, Block followed up with more surveys, looking again at personality, and this time at politics, too. The whiny kids tended to grow up conservative, and turned into rigid young adults who hewed closely to traditional gender roles and were uncomfortable with ambiguity.

The confident kids turned out liberal and were still hanging loose, turning into bright, non-conforming adults with wide interests. The girls were still outgoing, but the young men tended to turn a little introspective.