Found this on a couple of sites, apparently this is the originating link:
12 Reasons Gay Marriage will Ruin Society
1. Homosexuality is not natural, much like eyeglasses, polyester, and birth control are not natural.
2. Heterosexual marriages are valid because they produce children. Infertile couples and old people cannot get legally married because the world needs more children.
3. Obviously gay parents will raise gay children because straight parents only raise straight children.
4. Straight marriage will be less meaningful, since Britney Spears’s 55-hour just-for-fun marriage was meaningful.
5. Heterosexual marriage has been around for a long time, and it hasn’t changed at all: women are property, Blacks can’t marry Whites, and divorce is illegal.
6. Gay marriage should be decided by the people, not the courts, because the majority-elected legislatures, not courts, have historically protected the rights of minorities.
7. Gay marriage is not supported by religion. In a theocracy like ours, the values of one religion are always imposed on the entire country. That’s why we only have one religion in America.
8. Gay marriage will encourage people to be gay, in the same way that hanging around tall people makes you tall.
9. Legalizing gay marriage will open the door to all kinds of crazy behavior. People may even wish to marry their pets because a dog has legal standing and can sign a marriage license.
10. Children can never succeed without both male and female role models at home. That’s why single parents are forbidden to raise children.
11. Gay marriage will change the foundation of society. Heterosexual marriage has been around for a long time, and we could never adapt to new social norms because we haven’t adapted to cars or longer lifespans.
12. Civil unions, providing most of the same benefits as marriage with a different name are better, because a “separate but equal” institution is always constitutional. Separate schools for African-Americans worked just as well as separate marriages will for gays & lesbians.