I think it depends in the severity of the condition.
As I explained in the thread about termination, my DH's sister had a very severe genetic condition. Because of that, before getting married we did genetic counseling to check if DH could carry that condition. We were told by the geneticist that we didn't had more chances that the general population, but if the test had been positive, we would have taken extreme measures like a vasectomy. After seeing the suffering of his sister, we knew we couldn't risk getting pregnant by accident, let alone planning a pregnancy. We felt that was irresponsible and extremely cruel to the child and ourselves.