The bibliography concerning the proofs of the harmful influence of pesticides on spermatogenesis, male fertility and the fertility of couples, is already voluminous. Endocrine disruptors have a deleterious effect on the genitals of offspring over several generations. This solidly acquired knowledge hardly changes the use of these products. The most surprising thing is that it does not seem to undermine the very principle of their use; a new product dethrones another, suggesting that we always hope to discover incoherent products capable of destroying plant life without affecting animal and human life.
It was more difficult for us to predict that fine particle pollution (PM2.5 and PM10) would also one day have a dramatic effect on reproduction by increasing spontaneous abortions, neonatal mortality and prematurity. There is a clear decrease in birth weight under the effect of PM10, but also on other pollutants such as SO2, O3, CO and benzene. The inverse correlation between road traffic and birth weight is significant. Heavy metals have similar effects on spontaneous abortions, prematurity, neonatal mortality and fetal hypotrophy.
Critics of environmentalists will rejoice to learn that these pollutants are not the main cause of declining fertility in our developed countries. Indeed, the first cause is of a social nature: it is the increasingly advanced age of the first pregnancy. Despite all our progress, we have not been able to modify the optimal period of fertility, which remains between 18 and 36 years old, for both men and women, with a peak at 24 years old. Nature stubbornly prefers young gametes.
The phenomenon is well known in all countries: economic growth is always accompanied by a decline in the birth rate. When China was poor, it authoritatively imposed the only child, now that it is getting richer, it encourages the birth rate. Unlike other species where the availability of resources determines demography, in ours it appears that prosperity cannot be simultaneously economic and demographic.
Immigration is then the best solution for the demographic future of countries where infertility is social. However, with the globalization of nuisances, one can fear an internationalization of infertility. Which would be quite worrying for our species.
Catastrophist theories in geology and biology have been disproved by Lyell and Darwin. We can reasonably think that they will not be more relevant in ecology. Life and the planet will remain, the nuisances ofA wise man are only catastrophic for themselves. This is a particular prey/predator type balance since the same species plays both roles.
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