With overpopulation being as big an issue as it is currently, could it be possible that humanity would evolve to exclude sexual urges?
It may not be so bad if this were the case. Accidental pregnancy would become virtually non-existent, as individuals would most likely engage in intercourse for the sole purpose of procreation. With less people choosing to procreate, the number of pregnancies annually would greatly diminish and the population may be able to level out at a more sustainable level for the planet’s resources.
As many are beginning to believe that agnosticism and atheism are products of a religious evolution, the idea that asexuality is the same on a sexual basis may not be far off the mark. Perhaps it’s all part of a humanity cycle, and this being the case would simply be sexuality’s version of an ice age.
Short answer: Evolution does not work like this, and an individual randomly choosing not to reproduce would be immediately selected against; any genetic variants that produced such a phenotype would never have a chance to rise in frequency in a population past drift. (Assuming you’re assuming that asexuality = less reproduction, which may or my not be the case.) Nature does not care if a population outproduces the carrying capacity of its environment. Nature has a perfectly good answer to that, which is that members of that population will starve and die of diseases disproportionately until the population shrinks back to sustainable levels again.
There are a number of reasons that reproduction tends to shrink in populations over their environment’s carrying capacity, but these tend to be related to increasing competition with other individuals. If your kid has to beat out 100 other kids to get to adulthood and secure enough resources to grow large enough to reproduce, you need to invest in your offspring way more (or otherwise have fewer but better offspring) than if you kid only has to beat one other kid. Because of this, it’s a pretty common strategy for mammals to have fewer offspring and invest more parental care into them when competition is high for available resources.
Doesn’t have anything to do with sexual attraction, changes in sexual orientation, or the increase in people identifying as asexual. That last is probably the result of a complex interaction between heightened communication that the internet makes possible, the increased acceptance of sexual orientation as a model through which to understand sexuality (itself only about a hundred years old), and the work done by asexual communities to increase visibility in the past ten years.