Thematic Bible: What type of eunuchs there are

His disciples say unto him, If the case of the man be so with his wife, it is not expedient to marry. But he said unto them, Everyone cannot receive this word, except those unto whom it is given. For there are some eunuchs who were so born from their mother's womb; and there are some eunuchs who were made eunuchs of men; and there are eunuchs who have made themselves eunuchs because of the kingdom of the heavens. He that is able to receive it, let him receive it.