Let's stop talking about the slippery slope. A society that is debating making "marriage" between two people of the same sex (why stop at two?) a legal right has nearly hit bottom. Am I the only one who finds this an absolutely astonishing debate, something out of Federico Fellini's Satyricon?

It's because of this that the recent Vatican document condemning homosexual unions is heroic. At this juncture in history, anyone who questions the right of homosexuals to marry is likely to be derided as backwards or a hater. But the Vatican document, which contains some lovely passages, reiterates what Western (and Eastern) civilization has always understood about marriage: it is a union between a man and a woman. In the Christian tradition, this union is sanctioned by the Creator. "Marriage is not just any relationship between human beings," the Vatican warns.

Proponents of gay marriage believe the word "marriage" can mean whatever you want it to mean. This, says the Vatican, is not the case. Though there are numerous loving, longstanding, and arguably beneficial quasi-marriages between members of the same sex (this is me speaking, not the Vatican), these relationships are not marriages. Wishful thinking and the thoroughly modern notion that reality is malleable will not change this. "No ideology can erase from the human spirit the certainty that marriage exists solely between a man and a woman," the document states, "who by mutual personal gifts, proper and exclusive to themselves, tend toward the communion of their persons."

Most of us know homosexual couples whose company we enjoy and whom we admire. But this doesn't mean that the Church or the secular legal system should redefine the most basic of human relationships. "[R]espect for homosexual persons cannot lead in any way to approval of homosexual behavior or to legal recognition of homosexual unions," the Vatican document states.

Advocates of gay marriage insist that it will not injure the already fragile institution of marriage. How will a straight couple's marriage be affected by allowing gays to the right to marry legally, they ask. The answer is: We don't know. No civilization in recorded history has endorsed homosexual unions as commonplace, an obvious truth unless you have been suckered by the writings of various pseudo-scholars who, presumably using little Latin and less Greek, have "discovered" that such unions were widely accepted in the ancient and Medieval worlds.

So we don't know for sure. But there is also no reason to believe that traditional marriages would not be affected in ways we have yet to imagine by the sudden notion that marriage is anything you want it to be. If the meaning of marriage is changed, marriage will change. Even some advocates of gay marriage have suggested that allowing homosexual unions will introduce more latitude about extramarital sex. Gee, that should help make floundering marriages more stable.

One of the most unpopular passages in the Vatican document is the contention that homosexual adoption is wrong. "How can two loving adults who voluntarily take a child into their home be condemned?" say indignant liberals. Adding to the problem is the current moral status of the Catholic Church. Just when society might most benefit from listening to the Church's historic teachings on sexuality and the nature of marriage, the Church herself is so compromised by sexual sin within her ranks that many sneer at the notion that she has anything to say, especially about protecting children. Our mitered shepherds are to blame for this. Morally speaking, it's a perfect storm. But just because individual bishops have despicably failed to protect children doesn't mean the Church as a whole has nothing valuable to say about children's wellbeing.

Undoubtedly, there are children being raised by two homosexuals who are far better off than they would be elsewhere. There are single-sex families that mirror the traditional family more than some two-paycheck families today, with one gay partner quitting his job to be a stay-at-home mother.

My feeling on gay adoption is that it would be nice if we could just look the other way-that is, tacitly allow it without making it legal. Of course, this is impossible. Adoption is a legal act.

Not surprisingly, Holy Mother Church is not quite as namby-pamby as I am on the subject of gay adoption. In what is sure to be an oft-reviled passage, the document states that gay adoption does "violence" to the children. This doesn't mean that Rome believes homosexuals are prone to beat their children. But, if same-sex marriages are inherently disordered, as the Church teaches, children brought up in such environments live in a morally disordered universe. We do not really know what the future will bring for these children or for a society that permits widespread gay adoption. Of course, from a Catholic point of view, we don't need to know the far-reaching consequences to know if something is morally wrong. Not a very modern idea, is it?

In another controversial passage, the Vatican statement calls for Catholic politicians to uphold the idea that marriage is a union between a man and a woman. There has been talk that this puts some Catholic politicians in a bind. Would that this were so. Pro-gay marriage Catholic politicians will simply follow in the footsteps of those who call themselves Catholic and support abortion rights. The only difference: They won't dare say they are "personally opposed" to gay marriage.

The Vatican document and the renewed interest in gay marriage follow closely upon the Supreme Court's Lawrence decision overturning a Texas law that banned sodomy between homosexuals. The fallout from Lawrence is going to enliven the coming presidential election. My second favorite Supreme Court Justice, Clarence Thomas, was right in calling the Texas law the decision overruled "silly" in his dissent in Lawrence. But in basing the Lawrence decision on the privacy right, the Court opened the way for a debate on gay marriage--and lots of other stuff down the line. Why is incest wrong if your sexy big brother is willing and an adult? It seems that, if anything goes between consenting adults done in the bedroom, then it's morally right to snuff granny-as long as she's okay with that, and it's done in the bedroom. (We could call this new right "assisted suicide.")

One last note, a personal one: When I lived in the French Quarter in New Orleans, many and many a year ago, I knew a lovely gay couple. They had Sunday brunches at which one of them was always naked. He had a physique that would have thrilled Praxiteles, and he chinned himself on a bar while the guests looked on. I noticed something quite amusing: The more liberal and "enlightened" the guests were, the more shocked and embarrassed they seemed. Watching them trying to hide their discomfort was delicious fun.

I fear that many people, though secretly uncomfortable with gay marriage, will support it in order not to be labeled unsophisticated. There may also be an understandable desire not to hurt the feelings of respected and loved gay friends who favor gay marriage. But we aren't going to get off so easily.

The Vatican has asked us to stand up for what is true no matter how politically incorrect it may be. The simple truth is that marriage has always been between a man and a woman, and Christian marriage is the union of a man and a woman, blessed by God.