Getting back to the “nature vs nurture” thing, I have two cousins, both adopted by my aunt/uncle at the same time, when both were very young. The two cousins are not biologically related. One is very outgoing and participates in some risky behavior. The other is extremely quite and is working her way through college.
This is as close to a “scientific” trial as I think you can get without examining data on thousands of people. You have two children both adopted early on, with drastically different outcomes.
