The New York Times posted an article about an evangelical who couldn't think of a reason, other than what the Bible says, to oppose same-sex marriage (SSM). In lively discussions, proponents of SSM tell me that only religion stands in their way.

So let's come up with ten reasons to keep marriage traditional, without citing biblical commands.

Granted, each reason by itself could become a book, but let's go over them anyway, as reminders and conversation starters. Take them for what they are.

For the purposes of this article, a revisionist seeks to redefine or revise marriage. A traditionalist would like to keep it as one man and one woman.

1. To reproduce, nature favors heterosexuality, not homosexuality.

Nature is savage and impersonal. I don't share her unkindness, so don't shoot the messenger. But at the same time it would be wise if our beliefs were to correspond and cohere with her. She's also called reality.

Nature says all species must reproduce; otherwise they'll die out.

For example, any farmer wants his flocks and herds to multiply. He does what he can to make sure they do. If any "gay" sheep or other animals were to show no interest in females even during estrus, they don't prosper the farm. Why would the farmer grant them special treatment? (They can't even consummate their attraction to each other).

Recognizing the way of nature, a wise society fosters the one relationship that optimally helps society to thrive and live to see another generation: a man and woman who are able to consummate their relationship with their unique sex act and produce a child.

A functioning society is under no obligation to recognize other nonconformist relationships by conferring a special status on them. However, society should protect them from harassment, just as it does for other groups.

2. Nature teaches us to build the family unit and honor gender differences.

Nature is merciless, but she can be wise too. She made humans male and female, so our body parts have a natural coordination that reproduces children. The offspring of this sexual union are also male and female.

These complementary anatomical differences reflect real gender differences beyond just the sex act. Each sex brings to childrearing special and unique skills that match boys and girls, who are, after all, undeveloped male and female adults.

The most thorough study on childrearing concludes that the heterosexual, monogamous, biological parents are optimal for raising their children. Yet, whenever there are dueling studies about gender and childrearing (e.g. two opposite-sex biological parents are best for children, or two same-sex parents are just as good), it is best to rely on the obvious.

In this case, it's unwise to deny what we see with our own eyes: man, woman, boy, girl.

3. The essence of marriage is intelligible -- it makes the most sense.

After the first two points, we're ready to clarify the essence of marriage.

Succinctly stated, the essence of marriage is the permanent and exclusive covenant and union of one male and one female who consummate their monogamous commitment by their unique sex act, which is capable (or potentially capable) of producing a child.

Nature has made two opposite sexes. Therefore, two parents, one of each sex, raising their own biological son or daughter, are optimal for a healthy society.

But, revisionists ask, "Isn't committed love the essence of marriage?" In reply, love is strong, powerful, and beautiful, particularly when it's expressed in a commitment. However, this is not enough, either. Two best friends who have been roommates for many years can have a deep (nonphysical) committed love. So can two or more siblings -- maybe they enjoy a deeper (nonphysical) committed love than a married couple does. But they're not marriages.

4. Childless heterosexual married couples reinforce marriage, not redefine it.

An infertile or sterile heterosexual married couple cannot beget or bear children. In some cases they might not be able even to consummate their marriage with coitus, due to impotence or other problems. This too is the way of savage and impersonal nature. These couples don't fit the definition of marriage. So revisionists ask -- what about allowing two childless men or two childless women to get married?

However, these sad cases are reproductive malfunctions and do not add up to a strong position for revisionists. Historically the failure to consummate the marriage has been a cause for annulment or dissolution, while infertility and sterility have not. In any case, maybe some remedies can fix all of these reproductive malfunctions. Whatever the outcome of the remedies, these malfunctions certainly don't open the door to SSM.

Next, a fertile heterosexual married couple may decide not to have children. A postmenopausal woman marries a man. The woman's change of life is also the way of nature. These two married couples, young and older, don't have reproductive malfunctions. Now what about homosexual couples who remain childless? They too should be allowed to marry, say revisionists.

These heterosexual childless married couples don't redefine marriage beyond recognizable parameters. Their heterosexuality -- based on male and female anatomy and attraction -- is the link to the essence of marriage and reinforces it, not overturns it. They can still consummate it by the unique sex act.

5. Traditional marriage is strong, as is.

The divorce rate is reported to be 50%. Revisionists capitalize on that number and claim that marriage is being abused or reshaped. So, taking a non sequitur leap, they say traditionalists should be willing to redefine it.

That number is alarming, except for one thing. It isn't true.

According to the Census Bureau (2010), an average of 9.0% of males and 11.7% of females in all age categories and ethnic groups are reported to be divorced. According to a study done by Betsey Stevenson and Justin Wolfers, two Wharton professors, the divorce rate was 16.7% in 2005, down from 22.8% in 1979, among the "at-risk population" (those who are currently married). Whatever the exact number is, it is well below 50%. Marriage, though imperfectly practiced, is strong.

But hypothetically, even if marriage were broken, say, at an 80% divorce rate, then marriage still needs to be protected with a special status. This brokenness would not be a reason to redefine it, but to fix it. And if it ain't broke, don't fix it by adding other "marriages."

6. Some certainties should not be rejected or fundamentally transformed.

The heterosexual marital union between one man and one woman runs deeper than a cultural, artificial construct. Yet, hyper-skepticism, currently taking the form of postmodernism, says marriage has no essence, so we can "fiddle" with it as society evolves.

Though a definition of postmodernism is difficult to nail down, the Routledge Companion to Postmodernism says: "In a general sense, postmodernism is to be regarded as a rejection of many, if not most, of the cultural certainties on which life in the West has been structured over the past couple of centuries" (p. vii).

One gay activist who works hard at redefining marriage says: "In the end we will have so remade society, it will have to adjust to us, because it will seem absurd not to."

Will radical, iconoclastic leftists get their way again, as they seek to destroy another beautiful, stable and honored tradition?

7. History and democracy matter.

Related to the previous point, there is a long and meaningful history attached to marriage. That must mean something. Ever since the founding of America, traditional marriage has served this country well. If we change its essence, who can accurately predict the outcome?

However, Obama, changing his mind, now endorses SSM, and his administration refuses to defend the 1996 Defense of Marriage Act (DOMA), signed into law by the legislative and the executive branches. Will the Supreme Court decide to send the issue back to us and not redefine marriage for 310 million Americans in July 2013?

Given this muddled state of affairs, the political elites should no longer determine this issue. I'm willing to trust the people to make the right decision in referenda; I'll live with the results.

8. Preserving traditional marriage is a virtue, not "homophobia" or bigotry.

"Prop 8 Is Hate," rhymes the bumper sticker. "H8ter" and "homophobe" are common slurs. Traditionalists should not get defensive, as if the names have even the appearance of validity. They don't. So reject the labels in a debate.

Undeterred, a revisionist told me that if traditionalists take out the word "homosexuals" and put in "Chinese," then the "hateful bigotry" becomes clear. However, heterosexual Chinese who marry don't redefine marriage, but confirm it. A black man and Chinese woman who marry redefine race relations, but not marriage. But a Chinese man and black man who marry redefine both race relations and marriage. The debate is about redefining or keeping the essence of marriage, regardless of one's race.

Discrimination is harmful, in most cases. However, it's not widely acknowledged that sometimes discrimination benefits or at least doesn't harm society. To cite only three examples, the Constitution says a foreign-born person who later becomes an American citizen cannot become president: immigrant "discrimination." The Constitution says only a person who's thirty-five or older can become president: "ageism." In the Olympics, men and women compete separately: "sexism."

Sometimes tough decisions have to be made, and conferring a special and unique status only on traditional marriage outweighs any drawbacks that come from excluding nonconformist relationships (but see no. 10).

9. Upholding standards against other redefinitions is necessary.

Just a short time ago, homosexuals, who make up about 3.5% to 4.4% of the population, wanted just to be accepted. Fair enough. But now they're demanding marriage. Then they're going further. Some gays say that while they have their primary partnership, they allow hook ups with others. "It's a redefinition of marriage," says one.

Polygamists, who are less than 1% of the U.S. population, are also pushing for marriage. If polygamists win their lawsuit, will polyamorists, who also make up less than 1% of the population, be far behind?

So, if you redefine marriage to include homosexual relationships, how can you logically exclude other nonconformists? You can't.

Revisionists often ask, "How does gay marriage hurt my marriage?" That misses the point. It could also be asked, "How would polygamy or even incestuous marriage hurt your marriage?" (We should not yet worry about a woman who platonically married a dolphin).

Your individual marriage doesn't matter in the debate.

The point is that these nonconformist relationships muddy the essence of marriage with no end in sight.

10. Unmarried civil union is a fair and reasonable compromise.

"I have gay friends and family, and denying them marriage hurts their feelings," we're told.

Then let's compromise. After the give-and-take, no one is a hundred percent happy, but no reasonable person is a hundred percent unhappy, either. An unmarried civil union for gays and lesbians is a good compromise. They can have the legal benefits that heterosexual married couples have, like inheriting and hospital visits.

However, revisionists complain that unmarried civil unions don't have the same emotional content that marriage does; they're separate and unequal. But if the word "civil" smacks of a cold courtroom, a couple can find a liberal church to conduct a religious ceremony and call it a "sacred union." Or if they want neither the legalistic nor religious overtones, they can call it a "special union" -- or whatever suits them. After a while, people will get used to the name "union" and not think twice about it. Gays and lesbians can make their unions better than equal.

Conclusion

The monogamous, heterosexual union, consummated by the unique sex act between one man and one woman, is optimal for having and rearing children, thus ensuring that society can live another generation. The family thrives by the special relationship between the biological, opposite-sex parents and their children. Consequently, society thrives.

By recognizing this pre-legal, intelligible essence and its purpose, and by conferring a unique status on it, called marriage, a wise society teaches its members that it values this covenant more highly than all other arrangements. And so should society's individual members.

Society is under no obligation to honor other relationships with marriage. Gays and lesbians can have unmarried civil unions, instead. Compromises are often necessary, for the greater good.

So, rather than tearing down this unique and special union and covenant, revisionists should drop their destructive goal and gladly fight to preserve it.

Society needs traditional marriage above all other rivals.