[Genetic aspects of male infertility]

Cytogenetic investigations in sterile males showed that autosomal and sex chromosome anomalies can be responsible of the defect of spermatogenesis. Specific alteration of genes controlling spermatogenesis is excluded because all chromosomes are involved in the anomaly and breakpoints are distributed at random. In the aim to explain the spermatogenic failure, three mechanisms are proposed: X-autosome interaction, asynapsis, somatic lesion of the gonad, each mechanism might act alone or with the other. Beside chromosomal infertility, meiotic or sperm anomalies suggest the presence of gene mutations which interfere with the evolution of spermatogenesis or lead to the formation of abnormal spermatozoa. Insertion of technics of molecular biology in our researches could demonstrate the existence of these mutations; the same technics will allow to resolve the problem of the failure of a germ cell bearing a chromosomal anomaly particularly when this anomaly is balanced and involves the autosomes and not the sex chromosomes.