If you’re Christian I hope you don’t believe asexuality exists because you are implying you and/or others are immune from sinful lust, which is applying divine properties to humans and therefore defying crucial theological principles.
Sighinastorm has shown an intimate knowledge of the scripture that I don’t think I can build on from a Biblical sense- I can, however, build on it from the point of view of the Church and Church teachings.
Coming at this from an Irish Catholic point of view, I would say that asexuality where the asexual has a very restricted sexual desire, and would only have sex in order to procreate, would actually be advocated. Many Protestant denominations advocate a certain level of chastity from their congregation, and in some Catholic communities the doctrine of ‘no sex before marriage’ is taken very, very seriously. I’d even go so far as to say that it [asexuality] would fall under chastity, one of the seven holy virtues.
Additionally, asexuality is to do only with sexual lust. Lust in itself does not always involve sex, it can simply mean envy or intense desire. Defining oneself as asexual does not exemplify one from other forms of lust, thus not rendering asexuals exempt from sin.
It can be argued that asexuality where there is no desire to procreate, and in some cases to desire to form romantic bonds, would undoubtedly be looked down upon, particularly in Irish Christianity which takes a very family-centric attitude to it’s teachings on living a good life for God.
However, throughout the Bible we see that the holiest conceptions are without sexual intercourse, notably the Virgin Mary with the birth of Jesus and Sarah with the birth of Isaac- one had yet to have intercourse, the other too old for it. The holiest of saints lived their life without sex, such as Saint Therese of Lisieux who actually became a Carmelite nun in order to remove herself from the men falling in love with her.
In short, no, asexuality does not imply that anyone is removed from sin, but in fact in a religious frame is somewhat encouraged.