God didn't necessarily create marriage, but he created love

Marriage was created by man, after whom we named the holiday Valentine's Day.

Plus, even if allowing Gay Marriage is "harming" the individuals who choose it, it's their choice. Despite all warnings, if they continue to love who they want, then who are we to constantly scold them as if they know no better? Plus, it's within our First Amendment to be able to have free speech and free religious beliefs, and you can not force what you believe on others.