1. There is no practical basis of marriage rights for procreation. This is proved by the prevelance of men and women who remain married without having children, and the vast numbers of unmarried parents.
2. I wish that you would define what you mean by "contrary to the American experiment." No one is advocating gay marriage for all states. Many people are demanding their own state government recognize civil marriage as distinct from religious marriage, and that all citizens have equal rights to civil marriage.