Young Islamist gunmen from Hamas and their nationalist Fatah counterparts have until recently been killing each other in the streets of Gaza and the West Bank. Granted there are political and cultural explanations for such violent behavior. But the role of demographics - specifically the vast numbers of young men in the Palestinian Authority - must also be factored in if one wants a better understanding of events in the Arab-Israel conflict. Political scientist Samuel Huntington, author of The Clash of Civilizations, has argued that this huge reservoir of young men aged 15-30 provides a natural pool of instability and violence directed both internally, within Muslim society, and externally. When 15 to 24-year-olds make up 20 per cent or more of the population, a society shows a "youth bulge," in the words of Gary Fuller, director of population studies at the University of Hawaii. But it is Gunnar Heinsohn who's lately made waves in Europe with his book S hne und Weltmacht: Terror im Aufstieg und Fall der Nationen - Sons and World Power in the Rise and Fall of Nations, which focuses on the youth bulge phenomenon. Basically, he says, the young men are violent because no society can provide satisfaction for such large numbers of them, even if there were enough ordinary jobs, even if the quality of life were improved. They're not violent because they're frustrated or because they have too much spare time and no prospects. Nor are they violent because of their cultural milieu. A society with an overflow of young men simply can't reward such a large number of "sons" with enough respectability, goes the theory. So they find ways to earn a standing. They wage war to earn military heroism. Or they simply use an ideology that turns even death into an achievement - into "martyrdom." WHEN 15-29 year-olds make up more than 30 per cent of a society, argues Heinsohn, who's a social scientist at the University of Bremen, violence is practically inevitable. Young men start fighting for prestige and standing, positions their society simply can't provide in sufficient numbers. Remember that women in Gaza, where 47 percent of the population is under the age of 15, have between six and seven children. Huntington's original clash of civilizations thesis might be reformulated to suggest that the presence of a youth bulge contributes to the willingness of a society to justify violence on religious or moral grounds, writes Heinsohn. His book has been lauded by the popular German philosopher Peter Sloterdjik as being of singular importance in understanding current developments. Heinsohn sees the young men's claim to fight for the God-given superiority of their religion as merely an excuse. This is also what Zakariya Zubeidi of Fatah's Aksa Martyrs Brigades observed when he told a reporter: "It was always our choice to be fuel for the struggle. But our problem is now that the car burns the youth as fuel, but doesn't move. These kids are willing to be fuel, but many have been burned as waste." Heinsohn writes that until 1914 German women would have as many as 10 children. Some of these "sons" fought it out on the streets of the Weimar Republic in 1933. Had German women continued to have as many babies as the women in Gaza do today, Germany would now have a population of 550 million, and 80 million men between 15-30. "Would these young men be 10 times as pacifist as the seven million [young men] Germany has today?" Heinsohn challenged the audience of a late-night philosophy talk show on German television. He reckons it is much more likely that they would be throwing bombs in Danzig, Breslau and Stettin - reclaiming these cities for Germany. OF THE 27 biggest youth-bulge nations today, 13 are Muslim. A decade from now, Islamic countries will make up a quarter of the world's population. Maybe this is what the late Hamas leader Abdel Aziz Rantisi meant when he spoke of "the century of Islam." What does this mean for America? Demographically speaking, Washington can hardly afford to be involved in a two-front war. Facing a manpower shortage, Heinsohn predicts that a future America will leave its fortress only if its security is directly threatened. The Islamic youth bulge worldwide won't start to shrink until 2015. Against such demographic threats, America and Canada are the only geographic entities even theoretically capable of shielding themselves. The very thought of trying to do so would be anathema in most of Europe. Heinsohn contends that by 2030 many of Europe's more savvy non-Muslim youth will have already left for sanctuary in the United States. Sloterdijk, one of Europe's most prominent intellectuals, said of Heinsohn's argument: "Just like Das Kapital was for Marxism, this book is the key work to a new realism in a field that could be called demographic materialism." WHAT DOES all this mean for Israel? With only 600,000 boys under 15, Israel is already a demographic David. Worldwide, the Palestinian Goliath has something like a 3:1 advantage. And no one knows when the Palestinian youth bulge in the PA, as opposed to the rest of the world, will peter out. Heinsohn says the Palestinian population explosion can partly be blamed on European financial aid to the Palestinian Authority. He argues that had Europe made it clear back in the 1990s that the EU would no longer help subsidize 10-children families, perhaps Palestinian women would today be having two children, just like their Algerian counterparts. Palestinian children could no longer be "spared" for terrorist organizations. In Algeria, for instance, the violence declined dramatically in 2002. The Israeli fortress is already being built. Physically, it comes in the shape of the security barrier. Against the youth bulge further afield, recently ordered German submarines may provide a level of deterrence. PLAINLY, A key to reducing violence is to reduce birthrates. According to Heinsohn, this could be achieved through widespread knowledge of birth control measures and the will to use them. Such an option, however, is unlikely because of religious opposition among traditional Muslims. Interestingly, Europe once destroyed its own knowledge of birth control during the Middle Ages, as Heinsohn reminded us in an earlier study. After the Black Plague claimed 80 million souls, midwives were burned at the stake, in the name of Christianity, for teaching birth control. The long-term loss of this source of knowledge probably fuelled later youth bulges in Europe that made the era of colonization possible. As for the present, Heinsohn observes that a single woman in rural India on birth control pills would, in peasant circles, be denigrated as a virtual prostitute. She would risk undermining her marriage prospects and thereby a secure future. But this outlook changes dramatically, Heinsohn notes, "when a woman goes to Mumbai to work in the hi-tech sector... she will have 1.7 children, just like a European woman." We're not likely to see many women in Gaza working outside the home on salaries. Traditional society seems stagnated. It only adds to the rage of young men that sexual relationships outside marriage are unthinkable. At the same time, a degree of social standing is needed in order to get married at all, Heinsohn says. If his assessment is correct, it's hard to be positive about Gaza's future - and that can't be good for Israel. The writer, a Swiss university student, has traveled widely in our region.