To an outsider, this theory sounds like a really hard one to test. The hypothesis is that experiences in infancy condition adult behaviour, so someone would nee

To an outsider, this theory sounds like a really hard one to test. The hypothesis is that experiences in infancy condition adult behaviour, so someone would need to track a large cohort of people for decades. That kind of thing is rarely done. And that is just the start. Once it's been shown that bad parents have permanently bad kids, how do you demonstrate causality? Maybe there is a bad people gene that they all have. Maybe the cause is the physical effects of stress during pregnancy. Or the effects of alcohol consumption: no doubt that correlates with the kind of parental behaviour that's being blamed. Sure, you can look at adoption, twins, etc. At that point, we're talking about a really impressive series of experiments, which deserve a bit more than, "it's been scientifically verified," even in a newspaper story.