“She’s so totally not gay,” Rosie O’Donnell whispers to the camera as one of her adopted daughters, an ultra-feminine little girl, plays with a makeup artist’s nail polish and lipstick. The scene is from the oddly engaging “All Aboard! Rosie’s Family Cruise,” a new HBO film about the first-ever vacation at sea for gay families, chartered two years ago for 1,500 passengers by Rosie and her life partner Kelli O’Donnell. Whatever you think of gay marriage, and I remain unenthusiastic, the documentary has undeniable charm.

Rosie’s comment about her daughter is probably on the money; presumably she noticed that the child doesn’t take after Rosie herself, who’s about as girlish as Jackie Gleason. But God help you if you’re not gay and make a remark like this in the media.

I’m still getting angry letters, for instance, because of my description last month of the City Lights clerk who snapped “We don’t carry books by fascists!” when a customer asked for the new Oriana Fallaci book criticizing militant Islam.

My crime? Assuming that because the clerk seemed gay, he probably was, and writing that I didn’t see why such a person is so sensitive to the feelings of Islamists when one of the first things these people would do if they ever came to power in this country is crush suspected homosexuals like him beneath walls.

Just the other day, a man emailed demanding to know how I could have possibly thought the clerk was gay. I responded: ” An obviously gay demeanor isn’t proof positive that the clerk was gay, of course, thus my phrase ‘suspected homosexual.’ Just as we don’t know that people crushed beneath walls in Muslim countries are actually homosexual — only that the Islamists think they are, and that’s enough for them. So I don’t apologize for my description of the clerk. It was perfectly accurate.”

I thought that seemed reasonable, but no dice. “I will never again read another word you write!” replied my correspondent. Well, as Jack on “Will & Grace” might say, Oh, put a sock in it, Elizabeth Anne.

And I continue to disagree with Rosie O’Donnell’s pro-gay marriage message, even though this regularly gets me lumped in with gay-bashing religious right extremists. I actually consider my position essentially libertarian, although I’ve never managed to convince my libertarian friends of this. But why is further expanding the state into private living arrangements something anyone who believes in small government should wish to do?

Declining to legally recognize gay marriage may be mistaken, but I don’t see that it takes rights away from gays, despite all the increasingly hysterical arguments to the contrary. You can’t take away something that has never, in the history of the human race, existed in the first place.

I also think that legally recognizing gay marriage undermines the relatively recent (and therefore relatively fragile) concept of Western marriage – in which one man is permitted only one wife, not the traditional assortment of assorted concubines, and is therefore bound to her in an officially egalitarian relationship. No one arguing for gay marriage wants it to be marriage Saudi Arabian style, in which one partner basically owns the other and can dissolve the situation at will.

Yet Saudi Arabian marriage is closer to the primitive default option than marriage in free societies, and recent history suggests that when the rights and responsibilities of modern marriage are expanded to its ersatz versions, the real thing is taken less seriously and the old ways begin creeping back in like weeds. I don’t think it’s a coincidence that unwed dads forced to pay child support jostle for time on “Jerry Springer” with deadbeat dads who feel little shame in abandoning their wives and children.

These men practice a form of de facto polygamy for the same reason that dogs lick themselves, because they can. And although (as the fathers rights types always remind us) they have problems of their own – it probably is hard out there for a pimp – the real losers in these equations are women.

Gay marriage advocates correctly point out that general heterosexual libertinism has a far worse and longer history of undermining traditional marriage than the current movement to officially sanction homosexual partnerships. But why put yet another straw on the back of an already overloaded camel? This isn’t to say that gays shouldn’t have the right to live together in whatever domestic arrangements they choose, or register at Barney’s and invite their friends and family over for a ceremony and call it marriage. That’s their business. I just don’t see why taxpayers should have to subsidize it.

But I also don’t see why social conservatives can argue in good conscience against gays adopting children – not when, as Rosie O’Donnell regularly points out, 3,000 kids languish in foster care. No better testament to gay adoptive families than the five healthy beautiful children in the HBO film – adopted as drug-addicted babies by two gay men – who witness their parents’ “marriage” at sea on Rosie’s family cruise. I’m happy that the ceremony, whatever it actually was, made the kids happy, and I doubt it matters to them that their two dads can’t really fill out a joint income tax return.And good for Rosie and Kelli for starting what looks to be a successful new business, which they’ve named R Family Vacations. Before the Caribbean vacation depicted in “All Aboard!”, gay cruises were exclusively single-sex, adults-only arrangements. This summer the O’Donnells’ third gay family cruise, from Seattle to Alaska, is sold out with 2,600 passengers. I congratulate them on finding an unserved market niche, and wish them luck in expanding it. That doesn’t mean I think their personal arrangements need the stamp of government approval.

Catherine Seipp is a writer and visiting fellow with IWF. She also maintains a blog, “Cathy’s World.”