> There are enough cases of identical twins where one twin gets it and the other doesn't that we are certain it can't just be genetic. Strictly logically speak

> There are enough cases of identical twins where one twin gets it and the other doesn't that we are certain it can't just be genetic. Strictly logically speaking, this is consistent with it being genetic + random chance (where the odds are determined only by your genes) - meaning no identifiable environmental factors. Not saying it is (nor would I know).