Hasse Walum at the Karolinska Institute in Sweden has reported a fascinating finding: a gene combination that promotes monogamy in men. The Washington Post story actually states it that other way: a certain gene allele increases the risks that men will not stay monogamous. Men with two copies of this allele are at highest risk, one-copy men are in the middle, and men with no copies of this allele have the lowest risk of marital break-up.
This is a wonderful development. Genes are not destiny, they are just risk factors. Knowing your risks helps you develop work-arounds (if you are at high risk) or can increase your confidence (if you are at low risk).
I look forward to the development of an easy test for this allele. It should be entirely voluntary, but I hope it will be widely available.