From LA Times:
Right-wing pro-marriage advocates are correct: Monogamy is definitely under siege. But not from uncloseted polyamorists, adolescent “hook-up” advocates, radical feminists, Godless communists or some vast homosexual conspiracy. The culprit is our own biology. Researchers in animal behavior have long known that monogamy is uncommon in the natural world, but only with the advent of DNA “fingerprinting” have we come to appreciate how truly rare it is. Genetic testing has recently shown that even among many bird species — long touted as the epitome of monogamous fidelity — it is not uncommon for 6% to 60% of the young to be fathered by someone other than the mother's social partner. As a result, we now know scientifically what most people have long known privately: that social monogamy does not necessarily imply sexual monogamy.
In the movie “Heartburn,” the lead character complains about her husband's philandering and gets this response: “You want monogamy? Marry a swan!” But now, scientists have found that even swans aren't monogamous.
More here.
