Prenatal identification of paternity. HLA typing helpful after rape.

The HLA antigens system is extremely polymorphic, and HLA typing is now widely used for both the exclusion and the positive assignment of paternity. We have also used HLA typing for identification of paternity of fetal cells in a pregnancy detected a few weeks after the rape of a woman. The HLA typing indicated that the father of the fetus was the woman's husband, with a probability of 25:1 (96%), before the time the rapist could also be tested. Subsequently, the accused rapist was excluded as a potential father because he lacked all of the paternal antigens detected in the fetus. This prediction was confirmed after delivery.