[Parenthood diagnosis within a family. I. Algorithm and decision-making (author's transl)].

The knowledge of human polymorphism provides an invaluable tool in the analysis of parenthood. This paper deals with the fatherhood diagnosis within a family (presumed father, mother, children) and describes a computer program, called Fratrie, which identifies parenthood rejections and computes different decisional indices. The analysis of these indices points out a neglected index, the percentage of men rejected with respect to the (mother, children) set. We propose a new decisional strategy using this index.