Leviticus is often quoted by people who redefine Christianity to match their own bigotry. Leviticus is a book of old Judaic laws. Some are basic morality ("Lev 19:29 Do not prostitute thy daughter, to cause her to be a whore; lest the land fall to whoredom, and the land become full of wickedness."), others are hygeine related ("Lev 22:5 Or whosoever toucheth any creeping thing, whereby he may be made unclean, or a man of whom he may take uncleanness, whatsoever uncleanness he hath), and others had to do with differentiating the Jews from the surrounding cultures (Lev 19:27 Ye shall not round the corners of your heads, neither shalt thou mar the corners of thy beard.").
Leviticus calls for brutal punishments — Lev 21:9 calls for a priest's daughter to be burned if she "plays the whore", 20:18 calls for any couple that has sex during the woman's period to be exiled, 20:14 suggests that anyone who has a threesome should be burnt, and 20:13 calls for the death of homosexuals. Leviticus 20:9 even calls for anyone who fights with their parents to be killed.
Leviticus also contains 19:28 Ye shall not make any cuttings in your flesh for the dead, nor print any marks upon you: I am the LORD which many people erroneously believe refers to tattooing (it actually refers to a kind of cutting and ash rubbing done at pagan funerals). In any case, for Christians, the laws of Leviticus are not intended to be taken as anything but history — Jesus "replaced" them with a new covenant based in faith, not law (Romans 3:28).