ENVIRONMENT, SPERMATOZOON AND PROGENY

Over the last fifty years, the risk factors for infertility have incre ased substantially, particularly those due to the environment. Spermat ogenesis and spermatozoa can be affected by physical (ionizing radiati ons, microwaves, heat, cryopreservation) or chemical agents (cancer ch emotherapy, tranquilizers, pesticides, industrial solvants, some heavy metals, alcohol, cannabis, etc.). Some natural factors, as stress or paternal age, also seem to affect spermatogenesis and, particularly, t he age can be combinated with the previous ones. On the whole, these f actors are able to decrease male fertility through some changes affect ing sperm concentration, motility or morphology and so it is possible to describe populations subject to such a risk. Moreover, these sperma togenetic changes can lead to abnormalities in its offspring. In the s ame way, industrial solvents lead to a decrease in birth weight and th e cannabis leads to an increase of the ante or post-natal death. Moreo ver, the change of the paternal spermatogenesis caused by cannabis can be found again in similar with lead, benzodiazepines and alcohol. Con cerning the physical factors, some authors have shown that the childre n born from fathers exposed to radiations presented an increase of the probability of leukemia. In animal, post-implantation losses are more frequent when the father is irradiated or subjected to heat before ma ting. Finally, the paternal ageing and, in man, very young age, also s eem responsible for a gradual lowering in the level of progeny cogniti ve functions. On the whole, these data should lead to a preventive att itude which would be more affective before about thirty years of age t han after his period.