First you need to distinguish between such concepts as asexuality and antisexual, as they are often confused with each other. Asexuals - people who are not interested in sex. They do not have any diseases, and in the past they may well have a successful marriage, but have sex they prefer other types of leisure activities: reading books, learning foreign languages, and so on. Western psychologists seriously considering asexuality as a kind of orientation.
Antiseksualy are far more militant. They believe sexuality is a form of addiction and put it on a par with alcoholism and drug addiction. Believe that people's dependence on sex hinders their spiritual development, a negative impact on relationships, puts people on the same level of development with animals. Because of sexuality there are conflicts between groups of people with different views on it (as an example - homophobia). Also, some believe antiseksualy humiliating sex for the receptive partner, because they do not see the difference between a voluntary bond and sexual violence.
However, we can not say that the movement antisexual emerged in our time. In the Middle Ages such beliefs supported a number of churches, considering the sexual act sinful. Famous scientists and cultural figures ridiculed the desire of mankind to carnal pleasures, rip them from working. But through the centuries sexuality and instinct of reproduction every time wins.