Human Evolutionary Question?

As Chris mentioned, you might get increased chances of sterility as a result of selection favoring a gene (or genes) that provide some other advantageous effect. This is likely the best explanation for why any genetic components of homosexuality aren’t removed by selection. But natural selection can’t produce the evolution of complete sterility in an entire population. Any genes providing complete sterility would fail to get any copies of themselves into the next generation, and so would be outcompeted.

If a population goes sterile, it’s either going to be because of environmental factors, or because of inbreeding. In either case, selection would still favor any individuals that weren’t sterile. The reason it happens with inbreeding is that the repeated breeding with close relatives over several generations causes the number of different variations of genes in the population (the number of alleles) to go way down. If several genes get down to just one allele, and if those particular alleles don’t happen to work well together, then all kinds of physiological problems can result that natural selection won’t be able to do anything about (because there isn’t more than one allele to select from). A common such physiological problem is sterility or lowered fertility, and this has been a problem for some endangered species, including the Florida panther.

This would be a very difficult thing to do considering evolution and most adaptations for that matter take generations to develop, and for a population or certain species in this case humans to create another human that cannot create a human is highly unlikely. Especially when you put it into perspective and realize the entire group of people would have to be non-fertile for this to work. For a species (any kind) to produce offspring that cannot reproduce goes against the laws of nature. Organisms are essentially alive to reproduce and creating an offspring or sub-species which is not fertile is simply impossible. There will never be any organism human or non human to produce non reproductive offspring because there would be no point for the previous generations to reproduce and it would be the end of the organism/species as a whole.

The only way, in which sterile children will be produced, is if human beings mated with animals, or with a species different from their own. A human would not have, a degraded mentality to mate with an animal.