The general understanding of genetic disease is not great. There are people
who believe that there is a moral duty to dissolve a marriage if the parties are
even distantly related or if there is genetic disease involved. One of the most
widely publicized cases involved a biologic brother and sister who were
adopted by different families as small children. They met in adulthood,
married, and had three healthy children. Another person who knew of their
earlier relationship tried to force them to divorce. They quite rightly refused.
Couples should understand the genetic problem they face and the likelihood
that children will be affected. Once they understand their options, the parties
to the marriage will have to make their own choices. Whatever a physician
may advise, strong marriages will tend to survive; weak ones may not, and
genetic compatibility is often only a small part of the equation.