Perhaps your world is a perfect one and it isn't. In our world (OOC: and in RL) it often is, to one degree or another. My nation tries to be as fair as possible, and prevent problems arising, but we're not alone on our planet and thus have to deal with other nations and other peoples.
OOC: I agree. Too much of the time, the unfair starting places of different social classes and the inequitable distribution of opportunity creates structural barriers against heritability of crime... certain neighbourhoods and areas, from a sociological lens, have an effect of producing crime, even with very different inhabitants over a long period of time. Social disorganisation theory may be relevant here.
OOC:
I think we are talking about two entirely different things here. Markhov up there was arguing against a 'sins of the father' sort of deal, which is what I, apparently wrongly, had thought you were going for.