HETERO3

The mutation probably arose in the twelfth century, almost certainly in northern Italy. Several generations later, a Venetian trader married the local beauty, both most likely endowed with the copy of the young gene. Their son might have been the first human who felt the full impact of HETERO3. A tall adolescent with an inclination for romance, Marco Polo found himself embroiled in such scandal that his father and uncle had to carry him off on a journey across Asia, saving him from the revenge of various husbands and fathers. Twenty-four years later and dying of cancer, Marco returned to Venice, surviving long enough to dictate an account of his spectacular adventures. The court of the Khan and the lost lands of the Orient have fascinated generations of historians, but the unexpurgated texts are what remain famous among schoolboys: Tales of a thousand beautiful women lying down with the tall foreigner who leaves his seed in cities and villages across two continents.

But Marco Polo didn't invent the modern world. Venice was the premier seaport of its day. Its sons and their genetic cargo sailed across the Mediterranean. Where other travelers would drink and brawl, these warriors sought women of every color, every faith. By the fifteenth century, one in every four Greeks was at least heterozygote for the trait. Norse and the English populations grew taller and better looking. The Spanish Variant arose in Catalonia, and it proved particularly efficacious. Columbus' voyage ended without gold or spices, but he presented five native maidens to the spellbound court and stories of their exotic beauty captured the imagination of millions.

After that, every nation with seaworthy ships launched expeditions to the Virgin World. Some explorers were led by their worst impulses. Hernan Cortes planned to slaughter thousands in the brutish quest for wealth and power. But many of his conquistadors carried the gene, often as double doses, and young brown women smiling nervously in their direction was too tempting to resist. Large-scale defections transformed the invasion, beginning a much slower and far more profound event--which is one reason why modern Mexica has a one-in-three saturation level.

Every gene has positive and negative effects. The deleterious consequences to HETERO3 include cancers of the reproductive systems and high odds of heart disease and strokes. Even with modern medicine, double-dose carriers rarely survive to sixty. But these hazards only help to prove the benefits of the sex genome; positive gains often outweigh the liabilities. Sociologists have shown that twenty percent saturation incurs the most benefits to the average population. Violent male behaviors are reduced, while only a few percent of males carry two doses. But rise beyond one in five, and the early deaths and sexual addictions begin to sap the vitality from modern society.

Intriguing and underrated are the effects of HETERO3 on millions of daughters. Like their fathers, these women are unusually tall and often attractive, and given the right circumstances, they are likely to act on sexual impulses. Indeed, women might be the larger agents of true change in our world. Islamic societies have been transformed in the last centuries, in no small measure because young women inherited lust from their paternal, harem-loving fathers. Queen Victoria's public passions helped make free love the norm throughout the Empire. More than half of the American presidents were carriers, and their girlfriends and famous mistresses often held double-doses.

But not all assumptions prove true. Many average-looking, happily married individuals test positive for the trait. And according to surviving hairs, Isaac Newton was a double-dose, but quirks in his personality and long-term exposure to mercury made the genius live out his days as an apparent virgin.

Most successful actresses and actors hold the gene, or they claim to.

Yet the eminent American sex symbol did not.

Which proves once again what a genuine marvel of nature Marilyn Monroe was--a voluptuous angel, the shared dream of millions of HETEREO3 carriers, tragically murdered by the bullet intended for the president as she rode with him and with Jackie in that lustrous, loving Texas sun.