EVOLUTION OF THE MALE-FERTILITY AS A FUNCTION OF AGE AND RISKS IN PROGENY

Testicular ageing affects at the same time the individual and his lineage. In the individual, vascular, endocrine, blood testis barrier and Sertoli cells changes because of age lead a decrease of spermatozoa number and an alteration in their form and motility. These changes lead a gradual decrease of fertility. In the progeny, paternel ageing is responsible for new dominant autosomic mutations which themselves cause different malformations and perhaps for certain chromosome X linked recessive mutations. Moreover, in animal and man, paternal ageing seems responsible for a gradual lowering in the level of progeny cerebral functions. In man, very youthful age was also related to these effects. Maternal age did not appear to play a part in this event. On the whole, these results pose the problem of the optimum age for fatherhood.