My View Towards Gay Marriage

Love between people with the same sex is crazy. However, no one can say it is wrong in the perspective of liberalism. I am a liberal minded one and I don't intend to say liberalism is bad, but liberalism must be strict in the matter of morality and religion.
Basically, people have right to love anyone. So, why is gay marriage banned? Well, I am a moslem, and my religion forbids the same sex marriage as Koran has said that woman and man are created to become a couple. Thus, they can have descendants.