John Cheever was gay, or bisexual. His daughter, Susan Cheever, is a sex addict. Any connection? In the specific case, no one knows, but a new theory about the genetics of homosexuality predicts that female relatives of gay men will be heterosexual and hypersexual.
As evidence grew that male homosexuality is partly innate, evolutionary biologists wondered how it is that the genes responsible for the trait survive. This year, Italian researchers published the results of studies that suggest an answer. They elaborate a model in which two genes, at least one on the X chromosome, tend to make a carrier "androphilic." Men with the genes are drawn to men . . . as are women. The theory predicts that if you look at a pedigree that contains male homosexuals and bisexuals, you should also find women who have sex early and promiscuously - and who therefore are likely to bear many children. This two-gene model answers the apparent Darwinian paradox. Yes, male homosexuals are less fecund, but their fecund female relatives more than make up for the deficit in offspring, thus allowing the relevant genes to prosper.
An analysis of population genetics supports the hypothesis. The key finding is that maternal aunts of male homosexuals have more children than do corresponding paternal aunts. (Men get their Y chromosome from the father's side of the family, and their X chromosome from the mother's.) Also, mothers of homosexual men are more fecund than mothers of heterosexuals.
The model counts bisexual men as homosexual. It does not explain female homosexuality, which appears to be less heritable and more environmental. For those who find the statistics daunting, Slate has published a thoughtful popular summary of the findings.
If the theory holds, the "genes favoring male homosexuality," or GFMH, provide a buffer against extinction in lean times. When a population is under pressure, as say, in the face of famine, it may pay for it to contain women who are so sex-driven that they will procreate no matter the circumstances.
Of course, we have no information about the genetics of the Cheever family. But an interview in the New York Times today made me think of the androphilic gene theory. Susan Cheever, a noted writer and daughter of the truly distinguished author, John Cheever, discusses her newest memoir, Desire: Where Sex Meets Addiction. Ms. Cheever writes: "When my daughter was in the hospital and a lover of mine came to see if he could help, I went back to my apartment and slept with him. Moving men, doctors, lawyers, book salesmen - any man associated with a threatening change in my life became erotically charged, with predictable results."
In a line that may make many an author bitter and jealous, she says, "The book rep was a classic one for me too - the guy who controlled whether or not the book sold. And you know, he made the book a best seller." So: there may be more than one advantage to androphilia. Parenthetically, Susan Cheever has had three marriages and two children.
Time will tell whether the sex-linked GFMH theory holds up. Meanwhile it provides fodder for parlor games. Think of your gay male friends - and then their near female relations. It's cruelly amusing to think that his bisexuality, which so tormented John Cheever, may account for the perpetuation of his gene line via his correspondingly tormented daughter.
