Yes. If the parents have the potential to be carriers of the disease, they can have a child with the disease. To show you my logic, follow this. T is normal, but t is tay sachs. If the parents are Tt and Tt, they can have a 25% chance of a child having the illness.
Maybe it could be that their brains aren't fully developed and they are going through a lot of different hormones which makes things more intense emotionally.
I believe the answer is A. Drug Abuse. :)
