William Bennett and Andrew Sullivan may disagree on whether people of the same sex should be allowed to marry, but at least the two men concur on one thing: They both hate those damn polygamists!Earlier this summer, Bennett, one of America's most vocal defenders of so-called family values, and Sullivan, the author of Virtually Normal: An Argument About Homosexuality, debated in the pages of Newsweek whether two people of the same gender should be granted the legal right to marry. The confrontation was inspired in part by the increasing likelihood that Hawaii will eventually permit gays and lesbians to wed (other gays and lesbians, that is).The debate spilled out of Newsweek and into pubs and coffee bars, and buzzed about the Internet. But opponents of same-sex marriage always came back to the same argument, which has become known as the "polygamy challenge." If you let two men marry, the argument goes, why should we stop there? Why not let two men and a woman marry? Or one man and three women? Or two brothers? Or a father and daughter?Sullivan had heard this forensic tactic before, so he raised the issue himself in his Newsweek essay, attempting to distance same-sex marriage from "polygamy and other horrors." But in one sense, it didn't matter. Opponents of same-sex marriage had already opened wide a dark closetful of anxieties when they began brandishing the anything-goes defense. They had invoked images of a society without limits, rules, or restrictions, where anyone would be free to indulge in the acts our culture forbids. In short, they had made us confront our taboos.Taboos are a culture's superlaws. Most, though not all, are codified as illegal acts, but beyond being merely criminal, taboos cause us to feel abhorrence, revulsion, loathing. Social anthropologist Hutton Webster wrote that taboos are "self-enforcing thou-shalt-nots." The word taboo derives from a Polynesian term (alternately spelled tabu and tapu) that refers to strong prohibitions laid down by tribal chiefs to prevent contact between certain people and things, intended to maintain order and preserve the common good. By putting same-sex marriage in the same league as polygamy and incest, conservative commentators intended to link it with acts identified in our culture as not merely unlawful, but to be crimes against nature. And yet, in spite of their power, our taboos are not etched onto stone tablets. Divorced people were once whispered about as tainted and damaged goods. But today--with half of all marriages doomed to fail--a man who jilted his first wife is the GOP nominee for president. A century after the United States abolished slavery, blacks and whites who intermarried faced isolation, prejudice, and worse. Today, about one out of eight new marriages involving a black person is interracial, up from one in 38 as recently as 1970. Occasionally, landlords still refuse to rent apartments to unmarried couples, but cohabitation is so much a part of our culture today that it has received a seal of approval, of sorts: Several state supreme courts have declared that refusing to rent to unweds is unlawful discrimination.Until recently, menopause didn't exist in polite conversation; today, it's standard fare for best-selling authors and daytime talk show hosts. Transvestism has come out of the closet, too (although it seems that our culture is more accepting of black men who dress as women--from Flip Wilson to RuPaul to Dennis Rodman--than it is of white men who enjoy slipping into a simple shift and smart pumps now and then). Certain clothes were once deemed unfit to be seen on anyone at least in public: our undies. But the 1980s brought us pop icons like Madonna and rapper Marky Mark, who took the scandal out of skivvies by wearing bustiers and BVDs on the outside. Women who once shrunk in horror when told their brassiere was showing now cover their lacy underthings with see-through blouses, or none at all. The fashion seems to have passed for boys, but for a brief time, high school bullies who formerly took glee in giving shame-inducing "wedgies" to wimps instead proudly tugged the waistbands of their own drawers up and out of their trousers.Some taboos gradually disappear; others vaporize with stunning swiftness. For centuries, Catholics struggled to make fish sticks interesting each Friday. Then, in 1966, bishops in the US voted to lift the prohibition against eating meat on Fridays (except during Lent). Overnight, once-forbidden burgers and lamb chops became end-of-the-workweek favorites.One wonders if Catholics who suddenly found themselves queued up at the local burger joint on that first Friday gave much thought to what it was they feared just the week before. They might have noticed that taboos aren't simple matters of right and wrong. Regardless of how deeply entrenched a taboo might be within a culture, there are only a few absolute, universal no-nos. For instance, we may shudder at the idea of eating dog meat, but in some cultures pooches frequently find their way into the stockpot. Here, Bowser is a virtual family member; elsewhere, he's dinner. Is one culture wrong? When we hold taboos to the light of reason, we discover that they are upheld by a psychic force that sometimes has nothing to do with logic or hard science.What about polygamy?To begin with, it's alive and well. A site on the Web promoting education about non-monogamous lifestyles lists more than two dozen support and social organizations nationwide for people who believe it's naive and spiritually debilitating to commit to one spouse.Polygamy is tolerated by at least one major religion today. After Christianity, the faith with the largest number of adherents in the world is Islam--which permits, though doesn't encourage, a man to marry as many as four wives. (Muslim women, however, aren't granted the same right.) In some African nations, polygyny (the term for men taking multiple wives) is common. Nearly half the marriages in the Ivory Coast, for instance, involve a husband and two or more wives, although the practice appears to be losing popularity. Polyandry, which occurs when a woman takes on several husbands, is rare, but is known to be practiced in the Himalayas.When most Americans hear the word polygamy, though, they think of the followers of the Church of Jesus Christ Latter Day Saints, better known as the Mormons--even though the church hasn't condoned the practice of marrying more than one person since 1890. Church founder Joseph Smith introduced the doctrine of plural marriage to his followers in 1843. Smith allegedly had 50 wives. Many--though by no means all--devout Mormon men in the 19th century married more than one woman. But Mormons didn't view the doctrine as permission to build harems. They were merely following the word of God, as passed on to them from Smith, their messiah.Feminists claim that polygyny turns women into indentured servants, and that's undoubtedly true in some cultures. But a historian who has written about polygamy reports that wasn't the case with Mormon wives. Jessie L. Embry, author of Mormon Polygamy: Life in the Principle, interviewed the children of the original Mormon polygamists in the 1970s. Women were courted, she found, and were free to refuse marriage proposals. The marriages were marked by problems with favoritism, personality clashes between wives, and shortage of resources. But, says Embry, "the families I studied were able to deal with the problems they faced."Anti-bigamy laws passed by Congress in 1862 and 1882 have withstood Supreme Court challenges by the Mormons on the grounds that the laws violated the right to freedom of religion. In 1890 the church officially stopped sanctioning polygamy, although there are said to be renegade Mormons still practicing in Utah. What's more, a splinter sect of disgruntled Mormons formed colonies in Arizona and British Columbia that remain today.The BC colony, known as Bountiful, was rocked in the early 1990s by an ex-member's charges that she was subjected to sexual and mental abuse in a series of arranged marriages. In response, a group of 30 women from Bountiful met with a reporter from the Canadian newsweekly Maclean's to defend the community as a society free of substance abuse and runaways, where children are taught the importance of family values. Bill Bennett, ex-drug czar and author of The Book of Virtues, take note.In their application, bigamy laws are unmistakably patriarchal, too. According to A Guide to Sex Laws in the United States (University of Chicago Press; to be published in October), laws banning polygamy have mostly been used to prosecute fortune hunters--con men who travel from city to city, romancing and marrying women just long enough to empty their bank accounts before moving on to the next victim. Earlier this spring, a Utah man was arrested after marrying four women and systematically bilking each for thousands of dollars. John Weaver was charged with, among other things, bigamy and fraud. Naturally, Weaver should be prosecuted for his swindling ways. But do the courts really have any business trying a man for exploiting women's affections? If a car salesperson unloads a lemon on a woman, should he or she be required to refund the woman's money--and be further punished for making her feel naive and used?Unlike the 19th-century Mormons, there are plenty of polygamists today whose preference for the practice has nothing to do with religion. Brett Hill, editor of Loving More, a Boulder, Colorado-based newsletter for the practice followers call "polyamory," says he believes that the traditional two-partner romantic ideal "is unrealistic. It doesn't work for the vast majority of people."Hill calls the pattern of marriage and divorce that's so common in American culture "serial monogamy." Polyamory, meanwhile, actually stabilizes relationships by allowing partners to seek needs that are unmet in their current relationship from others--without the need to sneak around in adulterous relationships or abandon their original partner. Hill is part of a five-person heterosexual "marriage." He has a child with his partner, Ryam, who is legally married to another man; Ryam is also involved with a third man, who has another female partner.There are many advantages to the arrangement, he says (though he's quick to add that group sex is not one of them). Members benefit from more emotional support, more variety in their daily lives, and more money; five people can afford a new Trinitron more easily than two. And what about the children? Well, when Dan Quayle pilloried TV's Murphy Brown for glorifying single parenthood, his meaning was clear: Two parents are better than one. Polygamists would argue--well, you get the point.INCEST IS AN UGLY WORDWe equate it with fathers abusing daughters, and for good reason. There are more cases of father-daughter incest reported each year than all other forms combined. The portion of father-daughter couplings that could be called consensual is probably infinitesimal. The best word for all others is rape. And yet, as a taboo, incest is a complex matter. It is one of the rare universal prohibitions: No culture permits sex between family members. But at the same time, no two cultures completely agree on just who is and isn't a family member. For that matter, it's hard to find two states in the union that fully agree on who is off limits and who is a potential prom date.I'm referring, of course, to the cousin question. Say you're at a cocktail party when one of your friends hops onto the ottoman and clears his throat. "Attention, everyone," he says. "I have some great news: Cousin Betsy and I have decided to tie the knot!" Such a proclamation is bound to be met with an uncomfy silence, save for the smart-ass in the back of the room mimicking the banjo theme from Deliverance. Everybody else is too dumbfounded to speak, overcome as they are with visions of a 12-fingered child with no forehead. That's because we all know, naturally, that first cousins can't get married, since they're doomed to produce a baby with birth defects. This belief has been reinforced over and over again in movies and cruel jokes about inbred aristocrats and hillbillies.Contrary to popular belief, it's perfectly legal for first cousins to marry in 21 states (including Louisiana, birthplace of rock 'n' roll bad boy Jerry Lee Lewis, who married his 13-year-old first cousin, Myrna). Of the 29 states that prohibit first-cousin unions, five permit exceptions, typically when the bride is past child-bearing age or one partner is sterile, affirming our fears of spawning genetically inferior children. Which could be thought of as regulatory overkill, not to mention undue prejudice, since first cousins stand only a slightly greater danger than randomly paired mates of birthing a sickly child. "Yes, there is a greater danger," says University of Michigan geneticist James Neel. "No, it is not great."Neel originally reached this conclusion while studying the effects of atomic warfare on the Japanese after World War II. Marriage between first cousins was fairly common in Japan at the time, giving Neel a large pool of children on which to test the old wives' tale.His findings, which match those of similar studies, surprised him. "In the average child born to a first-cousin union, the chance of death before, let's say age 10, is increased about 3 percent," he explains. "The chance of some physical problem--from gross congenital defect at birth to defects of vision, hearing, and IQ--is also increased about 3 percent."To put that figure in perspective, consider that the March of Dimes says about 4 percent of live births in the United States result in some form of birth defect (defined as "an abnormality of structure, function, or body metabolism present at birth that often results in physical or mental handicap, or is fatal"). That means the danger of first cousins producing a genetically challenged kid is about 7 percent--which, compared to 4 percent, doesn't seem so wild and reckless. Certainly not the stuff of punch lines and prohibitions. Like many exaggerated fears, this one has a basis in science. Some genetic disorders, such as albinism and cystic fibrosis, require a double dose of the same recessive gene, one from each parent (who carry, but don't express the gene). A man and woman linked by blood are, in fact, more likely than two unrelated people to carry the same defective genes. But in the case of first cousins, the difference is slight.Fathers and daughters, sons and mothers, brothers and sisters--that's another story. Neel points out that the closer the blood relationship, the far more likely two people will share the same flawed genetic material. A brother and sister, he explains, are four times more likely than first cousins to produce problematic progeny.Then again, genetic testing has become sophisticated enough in recent years that if Sis and Junior really did want to make a baby, they should be able to find out in advance whether their genes were too similar. And what if they didn't care? If an unrelated man and woman who know in advance that they carry recessive genes for cystic fibrosis decide to have a child, are there laws preventing them from doing so? At least in theory, there is actually a societal benefit to breeding between conjugating cousins and siblings although it takes generations for it to be realized. Bad traits are bred out, since they are passed on within the blood line and not into the general population. Of course, once you get past questions of genetics, there are still nettlesome issues to resolve. After all, if a man marries his cousin, does he call her mother "mom" or "auntie"?TO EATEN HIS OWNIncest is just one of two taboos generally accepted as universal. The other category prohibits the eating of certain foods. However, while dining on human flesh is considered very poor taste in most parts of the world, the specific foods considered taboo in one culture may be a typical lunch in the next.At first glance, incest and food taboos seem to have little to do with one another. But they share the common theme of setting boundaries, explains Ben Orlove, an anthropologist in the division of environmental studies at the University of California/Davis. "With incest, you're establishing a boundary around the family," he says. "So, too, you could say that with food taboos we define the domestic human world, which includes the animals most closely associated with us."In other words, our culture discourages us from sleeping with certain family members just as it frowns on eating the family dog. But that sentiment isn't shared everywhere; dogs, it seems, are the first cousins of the animal kingdom.After all, there are populations throughout the world that eat dog meat. Restaurants where doggie dishes are served are common in Korea, for instance. Korean men, in particular, savor dog meat; nearly two out of three believe it to be an aphrodisiac. Even in this country, some southeast Asian restaurants are said to serve dog-meat entrees to diners who request "traditional" food.As I write, my terrier, Woody, lies next to me on a pillow, dozing. My wife and I dote on him as though he were a small, furry, quadrupedal child. I mention this in what I know will be a futile attempt to stifle assertions that I am a heartless canine-ophobe for even raising the following question: What is inherently evil about eating dogs?Before dog lovers demand that I turn in my leash, consider an analogy. As reported in the Seattle, WA weekly, Eastsideweek earlier this summer, the Puget Sound area is plagued by flocks of Canada geese, which foul lawns, golf courses, and beaches with their mushy greenish-black calling cards. One surprising proposal that's gaining support for dealing with the menace is to kill the birds, cook them, and serve goose dinners in local soup kitchens.If Canada geese are a nuisance, the problem of unwanted or rejected dogs and cats in this country borders on a national tragedy. According to the Humane Society of the United States, 8 million to 12 million animals are taken in by shelters in this country each year; half are never claimed and eventually put to death. (The Progressive Animal Welfare Society, better known as PAWS, in Lynnwood, is one of the few shelters in the United States to have adopted a policy of not euthanizing adoptable animals.) What if one of those shelters that regularly euthanizes dogs froze their carcasses and sold them to dog restaurants in North or South Korea? Better yet, take commerce out of the equation: What if the shelter gave away the canine cadavers to a social service group that ships food overseas to feed poor Korean families? It still wouldn't matter. The protests would be loud and angry.Those defenders of animal rights and dignity would find themselves picketing on shaky ground, though. Many of the same people who would oppose the dog meat trade would probably also tell you that they believe in multiculturalism and diversity--even as they were denouncing a culture for its choice of dinner ingredients. South Korea, an up-and-coming economic power, seems acutely aware of the way it is judged for this particular culinary practice. When the 1988 Summer Olympics were held in Seoul, government officials ordered dog-meat vendors to pack up and get out of town for the duration of the games. The world is watching, Korea seemed to say, and we don't want to be caught picking sauteed spaniel out of our teeth.Could America ever accept Korea's taste for what we strikes us as practically cannibalistic? Evolution in eating habits is inevitable in any culture. Foods with strange names from exotic lands that once seemed too foreign for our palates are now sold in fast-food eateries in strip malls across the nation. Furthermore, pasta and green salads have replaced steak and potatoes in many homes. It's probably no coincidence, Ben Orlove points out, that at the same time our Victorian rigidity toward sexuality has relaxed, too. "Imagine," he says, "Reader's Digest publishes articles on how to have fun in bed that never would have been published anywhere before."But as proponents of same-sex marriage have learned, there are still limits to how far the American mind is ready to open. "We're facing an era of change in both our diets and our sex lives," says Orlove, "but there's also concern about all this experimentation. Some people find that things are happening too fast." Which brings us back to the vehement backlash against same-sex marriage. In this era of exotic, healthier eating and attempts at sexual-taboo busting, says Orlove--only half-kiddingly--the anti-gay marriage movement is a bit like the resurgence of the steak houses. Just don't look for them to be serving loin of Fido any time soon.