It is not to crawl under a rock and hide. The bible states that Jesus is the same yesterday, today and forever. This means that what He said 2000 years ago applies to today. The wrong's on yesterday are the wrong's of today and tomorrow. The Lords value system has not changed with time.
People are inventors of evil things.
We want to change those things around us to fit our lifestyle, no matter right or wrong. The Lord is consistent and un-changing in his thoughts and ways. Sex bonds people together. If the bonding is with someone other than your spouse or an unnatural act this defaces the picture of God's covenant with his people. A marriage represents not only a man and women's dedication and faithfulness to one another it portrays Gods love toward his own bride which is the church.