Ocrenter, This can be a rhetorical question for thread purposes too.The poly genetic multi-factorial soup theory claims bring up lots of questions.

Yep I understand about the stress.
I’ll say in another way.Given that these families with tons of problems exist, in one of them with seven siblings in which, 3 are alcoholics, 2 are bulimics, one is an anorexic and one is hooked on seven things. How many have the genetic deviation? Would it be more than a family with the rarer case of spina bifida, if so why did it happen? We know these things run in families. Can the suspected genetic markers run as fast? Why what makes them so great? Would six siblings of the spina bifida and other similar issues have the genes but escaped because it is not post birth environment sensitive?

This question can be posed for any subsequent generation you like. Does it matter if both grandfathers and the father or this sibling group died of cirrhosis, as has been frequently the case?