The urge to have sex is powerful for most people especially during and after puberty when the body is full of hormones. Men apparently seem to have a higher sex drive than women. The average man apparently thinks about sex every seven seconds. It is part of our biological programming to have sex, and sex is the only natural way to produce offspring. Having sex for pleasure is probably a misfiring of this biological programming. If something gives you pleasure, you will want to keep doing it over and over again, right? The more you have sex (without contraception or any form of birth control) the more offspring you produce and the higher the probability your genes will survive over future generations. This was particularly vital back hundreds of years ago where most children died so you needed to have a lot of children so your genes would be passed on. Nowadays, the infant mortality in western countries is so low compared to many third world countries that the majority of offspring survive and now not really necessary to produce a lot of offspring. Natural urges such as the desire to have sex, or lust, as we should call it, had been suppressed for many years (probably because of religion and other traditions) and it was only until recently that we have started to embrace it more. The only way you can raise of family of your own is by finding a mate and having sex with him/her to produce offspring, unless you go to a sperm bank or something. If you pass on the genes that creates hormones causing attraction to the opposite sex and wanting to have sex with said opposite sex onto your children and their descendents, the more likely your genes will survive through them.
However, it does appear that many aspies are desexualised, lacking the sexual desires that NT's have. Though of course, if you don't have sex, your genes don't get passed on, including your aspie genes. In fact, you wouldn't even exist if your parents hadn't had sex and their gametes had fused to create you, and you quite possibly inherited the aspie gene from one of them. However, I wonder if the lack of sex drive in aspies has to do with the theory of group selection? Group selection suggests that when an organism, especially one of a social species, feels that they are not needed by the group (in this case the NT's as they're the majority) their biological programming goes into self-destruct mode. In other words, when aspies feel dejected because they feel they're not needed by the group (and let's face it, we aspies tend to go through it a lot more) we become depressed, we lose self-confidence and self-esteem, we lose motivation, and this is counterproductive to our survival because we need all those things to succeed. We become suicidal and of course we lose our sex drive so our genes won't get passed on. Sounds sort've like a self-genocide, but of course the aspie genes are recessive in some of the NT population and one day will become dominant in their offspring, so the aspie genes have not died out because of that. I know some aspies might say they're not depressed and yet they have no sex drive (and this might be to do with them not being able to relate to others), and there might be another explanation for this, but this one also seems to fit. It may be a politically incorrect, and do I endorse that sort of thing? No, but it's a logical explanation.
However, if we aspies felt accepted by society, I'm sure these counterproductive traits would start to dissappear (depression, suicide ect) and many aspies would then be able to fulfill their talents.