Yeah, that's not true... If you don't have any genetic diseases in your family, the change is very small that your child gets any diseas or deformation. If you do have genetic diseases in your family, the change of your child being sick, will double. If you do this two generations in a row, the change is four times as big, etc. Incest does not always mean that the child will be unhealthy or deformed. In contrary, if the family is healthy, the child will even have a slighter change of decease and deformation.Actually getting pregnant by Dylan or whoever is a realistic thing and a very probable thing if they will use no protection, the problem here though is that incest babies tend to be born unhealthy and/or deformed, not always of course but the chances are very high.
That being said, I like the idea of incest, I don't like the idea of of an incestuous child.
Also, I'm done with this game, it's just too big and too long.