~ Elton John ~
You may view my critique on same-sex marriages being the same, ontologically, as heterosexual marraiges, this paper is entitled, "Epicurean Romanism: Natural Law & Romans." Also see this case study, "Redefining marriage or deconstructing society: a Canadian case study," by homosexual psychologist, Paul Nathanson (it is multiple pages and I must h/t Come Reason Ministries via there podcast for this study).
Tammy Bruce -- a pro-choice lesbian, agrees with Elton John as explained in this article on her site, "Gay Marriage: Why Not?" (there is a more in-depth link that is connected with the article):