The finding is that a particular gene, plus having a lot of friends in adolescence, correlates with having politically liberal ideas as an adult. Sounds possible.
The kicker is the hypothesis by "the researcher and his colleagues" is the kicker:
people with the novelty-seeking gene variant would be more interested in learning about their friends’ points of view. As a consequence, people with this genetic predisposition who have a greater-than-average number of friends would be exposed to a wider variety of social norms and lifestyles, which might make them more liberal than average.The far-more obvious possibility, that people who seek social approval become liberals, does not even occur to them.
When adolescents eat more, or drink more, have too much or too little sleep, too many or too few sexual partners, or do anything outside the statistical norm, the focus immediately goes to some greater need for something-or-other that explains the behavior.
Or when children in studies have certain personality traits and grow up to be conservatives, we are treated to hypotheses of their greater need for control, or rules, or conformity, or some other pathological explanation. But since they grew up to be liberals, whatever they did that was different must obviously be something good.
What the hell is it with these people? They are supposed to, by profession, be alert for outside factors that bias their results.