> Also i'm convinced that sooner or later the trend will reverse, if necessary. Granted, this is not based on any facts. The way I see it, humans are animals a

> Also i'm convinced that sooner or later the trend will reverse, if necessary. Granted, this is not based on any facts. The way I see it, humans are animals and the average fertility of this species of animals has recently gone down radically in most places due to changes in it's habitat that has reduced its fitness. This has happened to millions upon millions of species in the past. One out of three things can happen: 1) The species goes extinct. This is more likely for species that are already pressured by competition from other species, since their ecological niche may go away completely. 2) The habitat reverts to a state where the average fitness of the species is high enough to sustain the population. This often happens in cycles for species like lemmings, where overpopulation periodically leads to population collapses. 3) If neither 1 nor 2 happens quickly, most species will adapt to the changes in their habitat. Often this happens by changing the relative frequency of genes in the gene pool towards those more fit to the new environment. This is arguably the main benefit of sexual reproduction. Sometimes a few mutations may also help adaptation. Given the current size of the human population, (1) is not very relevant (or if it happens, it's for another reason, such as runaway AI). (2) could always happen, for instance if society collapses to a point where condoms are not available and there's not police available to prevent rape. But if society remains relatively stable, I believe (3) will happen within 5-50 generations (starting in about 1950, meaning we're about 3 generations in). If I'm right, we will soon see that some genes are associated with higher fertility, and that the frequency of those genes keep going up over the generations. Since this is an exponential process, it starts out slowly.