[Calculation of the proportion of men excluded from paternity by HLA typing of the mother and child].

When filiation research shows that paternity is possible, French legislation recommends the calculation of two coefficients: 1. paternity probability (CP); 2. percentage of random men excluded from paternity by genetic markers of the mother and the child (PEme). A method is proposed, allowing the determination of PEme for the HLA system and PEme for the various systems employed. The calculations, relatively simple, can be worked out quickly and without risk of error, using a computer. We successively look at simple cases, complex cases and unusual cases: maternal death, consanguinity problems, racial problems. HLA-A, B, C, DR, DQ typing almost always leads to the exclusion of more than 98% of innocent men (PEme greater than 0.98). The HLA system clearly appears to be the most conclusive of the systems utilized by experts.