That's the thing, they didn't think. They didn't consider what the effects of their disease would have on a child. They just wanted a baaaaaaaby and this oreogre was born. Honestly though, this was something I really struggled with before deciding to have my son. My husband and I both have family history of things like heart disease, cancer, fibromyalgia, and autism... But the one that worried me was the mental illness. I was disgnosed with depression pretty much when puberty hit, and I've been told I will always have it. My shrink thinks I inherited it from my grandma, which is why I was (and still am) so worried of passing it on to my son. But I will be diligent in watching for warning signs and getting him treatment if he does develop depression.