Blue Blood.

Although Spencer Wellington (Howard Hickman) comes from an old, aristocratic family, he carries a bad gene. His doctor, John Rand (George Fisher) recommends that he never marry, but Wellington ignores his advice and weds Grace Valiant (Mary Mersch), who the doctor himself loves. Grace checks out Wellington's family tree and discovers the gene, but she's already pregnant. She gives birth to a child with a birth defect that kills him.