Same-sex marriage is immoral--philosophical and economical arguements

Same-sex marriage is a hot topic. I am opposed to it for philosophical, pragmatic, economical and religious reasons. While some regard religious reasons as irrational and pointless, they are the most powerful, but I'll save them for last.
Philosophically, if everyone in the entire world did some action and our world was a better place, that is a moral action. Conversely, if everyone did this action, and our world would be worse off, then that is immoral. If everyone in the entire world were homosexual, our world, our species, would be in bad shape. Therefore, why should I uphold what I philosophically oppose?
Pragmatically, religious and other semi-religious organizations (such as the Boy Scouts of America) oppose homosexuality, and they are being punished for doing so. The Catholic church in Massachusetts for a century placed orphans into loving homes. But because they religiously opposed putting orphans into homes of same-sex married couples, they lost their adoption license. Other religious organizations are being penalized in other ways. Pragmatically, our society depends on religious organizations to teach citizens to be morally upright. Society will not function if its citizens are immoral, only obeying the law out of fear of punishment. Societies need religions to do what government can't do: instill values into the citizenry. Don't punish religion because religion warns of (divine) punishments!
Economically, I oppose allowing same-sex couples to enjoy the tax benefits of marriage. A "byproduct" of marriage is another generation of tax payers. Same-sex couples physiologically do not make more tax payers.  Here me and my wife are, making another generation of tax payers (which is not the most easy job in the world), dumping money into the economy (or at least the disposable diaper sector, the child textile sector, etc), and instilling moral values into the future adult citizens of the nation. Why should same-sex couples get spousal tax benefits, spousal social security, etc. when between the spouses, they physiologically don't make tax payers to support them?
Religiously, I know that morality isn't relative; it is absolute. Science depends on absolute standards so that results can be compared between labs, generalized to other fields, and applied for the benefit of humanity. Can you imagine what science would be like if every scientist measured distance in their own footsteps? Religion and science have different ends, but similar means: they both convey (the discovery) of truth. Why should we allow science to have absolute standards, but deprive religious people of their claims of absolutes?  Homosexuality is immoral, and that is an absolute truth.