I can personally attest that there are asexuals out there (my wife is one). Often asexuals will engage in sexual activity when they are younger simply because of societal expectations. Young asexuals are often unaware that this is a naturally occurring condition. Then there are those asexuals who force themselves unnaturally to engage in sexual activity in order to obtain the security/advantage of a spouse (or have children). These people are vile, manipulative parasites.
I know quite a few myself. Some of them I think are too young to understand, but some of them are grown adults who feel no attraction towards either gender/sex. So, yeah, there are asexuals/aromantics in society.
Fluff, fluff, fluff, fluff, fluff, fluff, fluff, fluff, fluff, fluff, fluff, fluff, fluff
It is not that rare actually, many people just don't think about sex and think that is what I must do.
Asexuals are a parent's view of the perfect friend for their kids. Their whole point in life is not to impregnate, or get impregnated by their kids. I mainly typed this last paragraph to get past the minimum # of words.