Christopher, What is "homosexual sex"? Is it only anal intercourse? Do you believe that only gay men have anal intercourse? Your evidence that homosexuality is a public health threat doesn't include anything relevant to lesbians. If only male homosexuality is a public health threat, how should the law treat lesbians? What exactly are the harms caused to society by legalizing same-sex marriage? It's been legal in the Netherlands for just over 11 years. In Belgium it's been legal just short of nine years. Spain it is just shy of seven years. And in Massachusetts it has been legal for eight years exactly (May 17, 2004). There are several other US states and foreign countries that have legalized same-sex marriage in the last five years. Enough time has elapsed and same-sex marriage has been made legal in enough jurisdictions for its opponents to specify the harms it causes to society at large. What are they? You also mentioned that you believe individuals in monogamous, state-sanctioned relationships are most "happy." If that's true, is it then shocking that gay men are less "happy" if they are barred from such relationships? If you concede that you cannot make a homosexual turn heterosexual and that society should endeavor to make people more "happy," then why not permit state-sanctioned same-sex relationships? Wouldn't that also reduce the purported public health risks you note?

Also, on the persuasion front, as is noted by Posner in the original post, the most effective lobbying for gay rights is not done by what gays and lesbians say or argue, but by simply living out lives. Several studies support that hypothesis, including http://psychology.ucdavis.edu/rainbow/html/comeout1.html.

TANSTAAFL, Lady Gaga and Katie Couric? Lady Gaga I sort of understand, but why Couric? For what it's worth, I'm using Gallup to gauge the success of marriage equalty proponents' successful efforts at persuasion. http://www.gallup.com/poll/154529/half-americans-support-legal-gay-marriage.aspx What metric are you using? And I'm ok with being called a faggot. As I've been told by my lesbian friends that I am both gay and lesbian, you can call me a dyke too if you'd like, though it'd probably be confusing to a lot of people. I'll let you decide whether you're ok with being a called homophobe. Remember, it's your choice entirely.

Mark Brown, Studies supporting the original commenters position include: http://pediatrics.aappublications.org/content/109/2/341.full.pdf http://www.nllfs.org/images/uploads/pdf/nllfs-quality-life-january-2012.pdf http://www.ca9.uscourts.gov/datastore/general/2010/10/27/amicus29.pdf The final link is interesting in that it is part of the record in Perry v. Brown. One of Judge Walker's findings of fact in Perry v. Brown is that, "[a] parent's gender is not a factor in a child's adjustment. An individual's sexual orientation does not determine whether that individual can be a good parent. Children raised by gay or lesbian parents are as likely as children raised by heterosexual parents to be healthy, successful and well-adjusted." http://documents.nytimes.com/us-district-court-decision-perry-v-schwarzenegger#document/p97 Walker could conclude as such because the defense could not provide any credible evidence that it was inaccurate. Walker found one of the defense's expert witnesses to be lacking "the qualifications to offer opinion testimony."

It's interesting that while this debate raged in the comments, Governor Lincoln Chafee, a former Republican Senator and now independent Governor of Rhode Island, issued an executive order declaring that Rhode Island will recognize out-of-state same sex marriages. For a small state bordered on two sides by states that already recognize same sex marriage, it's effectively the the ninth state to recognize same sex marriage. It's the third state to do so just this year.

" Gay marriage proponents seem disinterested in persuading others to accept their viewpoint." http://en.wikipedia.org/wiki/Public_opinion_of_same-sex_marriage_in_the_United_States Scroll down to the chart under the heading "Older Polls." For a group disinterested in persuasion, those proponents have had rather incredible success in changing public opinion over the last 16 years. Either you are incorrect that proponents are disinterested in persuading opponents, or the argument in favor of marriage equality makes itself. I'm inclined to believe it's a little bit of both.

"Gays already have everything that goes with the word 'marriage', including the part I consider inappropriate: equal status as foster parents." How are you defining "marriage"? Your statement isn't even correct in those states permitting same sex marriage. Those couples cannot file joint federal tax returns, for example. Nor can a Massachusetts female citizen married to a French female citizen sponsor her partner for a U.S. permanent residency even though they are legally married in the eyes of the Commonwealth of Massachusetts. How can a same sex couple in Tennessee have the same rights in marriage as a married heterosexual couple when the Tennessee constitution specifically prohibits same sex marriage? Or in Virginia in light of the Marshall-Newman Amendment?