Jesus never mentioned homosexuality, so it isn't wrong.
This is a popular one, and is used a lot to argue that you can be Christian and gay. It isn't well thought out though, and here are a few reasons why it can be tossed out the window:
1) The whole Bible is God's Word, not just what Jesus said. There's that verse about all Scripture given by inspiration of God..... and there are several verses in the New Testament alone that says it is wrong, so you can't ignore the rest of the Bible and just live your life by what is in the four Gospels.
2) There are other things Jesus didn't mention, but we know are wrong. Bestiality, incest, drugs, listening to Justin Bieber........ so to say something is OK because He didn't name it out, is an empty and foolish argument to make.
3) In Matthew 19, Jesus said “he who created them from the beginning made them male and female, and said, ‘Therefore a man shall leave his father and his mother and hold fast to his wife, and the two shall become one flesh’” (Matt 19:4-5)" No, He doesn't specifically mention homosexuality or gay marriage, but it sure sounds like He singled out marriage as between a man and a woman.