Marriage is a holy covenant, designed by God, between a man and a women. The primary purpose of marriage is for the conception and rearing of children. People who marry may choose to not have children, but it still does not negate the purpose of marriage. Anything outside of God's design for marriage and sexuality is a perversion since it perverts God's design.
Christian's views in regards to sexuality are concurrent with natural law. It can be objectivity stated that a man's body is sexually designed for a female's body, and the primary purpose of sex is procreation. We were created in the image of God and given the gift to create other's in His image. This is God's design.
Today, however, marriage has become redefined and watered down to include same sex marriage. The ease and acceptance of divorce along with the decline of Judaeo-Christian ethics and acceptance of pagan philosophies and practices have helped to pave the way. It is what I like to call creeping paganism and has become all pervasive in our world today. The consequences of gay marriage and the replacing of Judaeo-Christian ethics with pagan vices will not immediately be felt or known. But I can offer a few predictions:
1. Marriage will continue to be redefined until it no longer has any real meaning or value.
2. It will open the door to more sexual perversions, including but not limited to pederasty and pedophilia (ancient Greece\Rome is a good example of this).
3. People of faith who believe in traditional marriage and values will be marginalized and discriminated against. If left unchecked discrimination will lead to persecution.
4. LGBT issues will be taught to children without the consent of parents.
5. All moral boundaries will be erased
6. Paganism will be the dominate belief system
7. Societal breakdown
8. Moral objectivism replaced with moral realtivism
To a degree many of these things are already happening, but it will get much worse. This creeping paganism has crept into our churches, entertainment, politics, schools, and culture at large. To often people have been intimated, shamed, and guilted into capitulation. And too often people have let it happen, bent the knee, and submitted, especially Christians. We have allowed our beliefs to be compromised and to accept pagan practices, but the choice to surrender is ours.
The Roman legions used to carry around what was called a Standard. It was a flag, banner, or pennant that was attached to a pole. The Standard was a rallying point and a symbol of pride. So important was the Standard that great efforts went in protecting it and recover it if it was captured, battles were even fought over them. Christians have their own standard, it's called the Bible. It is far more important and the truths it contains should also be protected and fought for. We shouldn't compromise or surrender when it comes to our convictions, no matter the cost. Don't be afraid to stand up for what you believe in, and never back down.