What is “reproductive equality”? It revolves around that core value of Western culture — monogamy — as opposed to that old “heathen” custom, polygamy.

Islam is the only major world religion that sanctions polygamy. Mohammad allowed his followers to have four wives (the same number he had). About 12 percent of marriages in Moslem countries are polygamous. This is not as bad as East and West Africa, where successful men often take more than a hundred wives and where almost 30 percent of marriages can be polygamous. But the solid core of polygamy at the heart of Islamic culture is enough to produce its menacing social effects.

What are those effects? Do the math. Into every society is born approximately the same number of boys and girls. If they pair off in monogamous fashion, then each one will have a mate — “a girl for every boy and a boy for every girl.” In polygamous societies this does not occur. When successful men can accumulate more than one wife, that means some other man gets none. As a result, the unavoidable outcome is a hard-core residue of unattached men who have little or no prospect of achieving a family life.

The inevitable outcome is that competition among males becomes much more fierce and intense. Mating is an all-or-nothing proposition. Women become a scarce resource that must be hoarded and veiled and banned from public places so they cannot drift away through spontaneous romances. Men who are denied access to these hoarded women have only one option — they can band together and try to fight their way into the seats of power.

AND THAT IS WHAT happens, endlessly. The entire history of Islam is a story of superfluous males going off into the desert (literally or figuratively) and deciding that the religion being practiced by the well-furnished elites of the cities is “not the true Islam.” They then burst back upon the cities, violently attempting to overthrow the established authority. The Shi’ites, the Wahabis, the Assassins (yes, that’s the origin of the word), the Muslim Brotherhood — all are the fruit of this eternal warfare in Moslem societies between the “ins” and the “outs.”

The only defense Islam has been able to construct for itself is to recruit these unattached males, inculcate them into the religion, and convince them that if they turn their violence and sexual frustrations outward¸ they will be rewarded with “70 virgins in heaven.” This is how the ranks of martyrs and suicide bombers are created.

Martyrs and suicide bombers are men who have internalized the fundamental axiom of polygamous society — that some men are expendable. When Muslim warriors proclaim, “We love death,” they are not kidding. Golda Meir said famously that the Palestinian conflict would end when Arabs loved their own children more than they hated Israelis. That moment is not likely to arrive any time soon. In a polygamous Islamic society, some men’s lives have very little intrinsic value. They are literally better off seeking death.

Monogamy, on the other hand, fulfills the proclamation that “All Men Are Created Equal, that they are endowed by their Creator with certain unalienable Rights, that among these are Life, Liberty, and the Pursuit of Happiness.” Monogamy is the social contract — albeit poorly understood and little appreciated — that lies at the heart of the relatively peaceful societies of Europe and the Orient.