Genetic aspects of human infertility.

Mutations of the human genome associated with the phenotype of infertility are well known. Some of these are visible under the microscope as specific chromosome mutations. Others arise from genes which function only in the germ line, or which function during development of the gonads, or which function also in non-gonadal somatic cells, in which cases sterility is manifest as a pleiotropic effect of dysfunction of this gene also in certain gonadal cells. Examples of mutations are presented in this paper. They indicate that men with a severe idiopathic sterility factor have an especially high risk for a genetically determined barrier to reproduction.