There are many sexual orientations, such as heterosexual, bisexual, homosexual, pansexual, polysexual, and others. Among the ‘others' is asexuality, which is actually where the person is just indifferent about any sexual feeling at all.
Originally thought to be some kind of psychological disorder, asexuality can actually be classified as a type of sexuality. Some people are just into that kind of stuff, and others, not so much. It's not entirely accurate to say that "everyone is born to do it," because some people just don't feel those feelings of attraction for others like most of the population does.
Asexuality isn't only documented in humans, but also in a wide variety of animals. It occurs naturally as a type of orientation that you're born with. Unfortunately, there is very little scientific research that understands asexuality in humans; most likely because it's only known to affect anywhere between 1-3% of the population.
The small amounts of studies that have existed on the matter have proven that women are more likely to have asexual qualities than men are, and that the orientation can be influenced by cultural factors, such as the type of life that they're born into.