In 1996, their son Gabriel Michael was born prematurely and lived for only two hours (a sonogram taken before Gabriel was born revealed that his posterior urethral valve was closed and that the prognosis for his survival was therefore poor). While pregnant, Karen Santorum developed a life-threatening intrauterine infection and a fever that reached nearly 105 degrees. She went into labor when she was 20 weeks pregnant and allowed doctors to give her Oxytocin to speed the birth.
Karen Santorum wrote a book about the experience: Letters to Gabriel: The True Story of Gabriel Michael Santorum. In it, she writes that the couple brought the deceased infant home from the hospital and introduced the dead child to their living children as "your brother Gabriel" and slept with the body overnight before returning it to the hospital.