Here is what Jesus said about the topic:
Matthew 19:12For there are some eunuchs, which were so born from their mother's womb: and there are some eunuchs, which were made eunuchs of men: and there be eunuchs, which have made themselves eunuchs for the kingdom of heaven's sake. He that is able to receive it, let him receive it.
So according to that, you could be one of the following...
1. Born that way: We hear the ultimate perversion of this on a regular basis these days. I am thinking that this one has to do with physical/mental limitations. Thoughts?
2. Made by men: This one reminds me of monasteries that require it. 1 Timothy 4 covers this though saying that it is the result of seducing spirits and the teaching of devils to forbid others to marry.
3. By choice for the kingdom of heaven: This is the case for Apostle Paul.
Jeremiah was called by God to be single (a lot of people know this, but do not know why):
Jeremiah 16:The word of the Lord came also unto me, saying,2 Thou shalt not take thee a wife, neither shalt thou have sons or daughters in this place.
However, it was not because it was not God's will for him. It was because it was God's will for him to not suffer the following fate...
3 For [because] thus saith the Lord concerning the sons and concerning the daughters that are born in this place, and concerning their mothers that bare them, and concerning their fathers that begat them in this land;
4 They shall die of grievous deaths; they shall not be lamented; neither shall they be buried; but they shall be as dung upon the face of the earth: and they shall be consumed by the sword, and by famine; and their carcasses shall be meat for the fowls of heaven, and for the beasts of the earth.
So I would say that unless you received a word from the Lord like Jeremiah, then you are not called to be single. However, you could "choose" to remain single like Apostle Paul.