Biological Advantage of Gay Uncles

(This is written in response to Yawning Bread's latest article It's my gay uncle who takes me to school every day or you can refer to the sampler page. Please go read the full article first if you haven't.)

Specifically, Yawning Bread mentioned that a recent study found that "Mothers with homosexual sons had 2.7 children on average. Mothers without homosexual sons had 2.3." He then went on to explain the potential benefits that a gay son may have to a woman that may allow her to be more reproductively successful, i.e. an additional male to provide support the other children and the children of the daughters, especially in situations where the fathers may be absent or lacking in loyalty.

I felt that at a deeper reading of the figures, there appear to be a potential paradox in the figures, which I would like to point out in case other readers also stumble upon the same conclusion. And then, I would attempt to, upon even deeper consideration of the figures, explain it away.

A woman having one homosexual son, and as a result have 2.7 children on average, although more than the 2.3 children of one without homosexual children, would on the surface still be less reproductively successful. Why is that the case? Well, if a woman has 2.7 children, but one of son is homosexual, that technically leaves only 1.7 reproductive children, vs the 2.3 reproductive children of a woman without a homosexual son. So on the surface, it thus appears to be less reproductively viable to have homosexual sons, and thus, through the process of natural selection, would have died out from the maternal gene pool.

Upon pointing out this apparent contradiction, I want to then highlight that the above analysis have glossed over an important detail, that the number of productive male children vs female children would differ. Why is that so?

Take the case first of a woman who has a homosexual son and thus produces 2.7 children on average. What this means is that, on average, she would produce 1.35 sons and 1.35 daughters. Considering only the productive children, she would produce 0.35 productive sons and 1.35 productive daughters on average.

As for the case of a woman without a homosexual son and thus produces 2.3 children on average, she would produce 1.15 productive sons and 1.15 produce daughters. So, you can see that although a woman with a homosexual son produces fewer productive children on average, she produces a larger number of productive daughters on average.

Thus, one could conclude that situations where productive daughters are more valuable than productive sons will tend to lead to societies where women producing more homosexual sons, and societies which are more accepting of them.

(Whether this is a result greater tolerance of males to eventually "become" homosexuals, or an actual expression of a genetic bias to produce homosexuals is, in this case I feel, a moot point. And those skeptical of the second option should be aware that phenotypic expression of genes are seldom absolute but often triggered by specific conditions in the environment.)

So what are the possible scenarios where productive daughters are more valuable than productive sons? I'm no trained anthropologist but I can hazard a few guesses. One scenario has been postulated by Yawning Bread - societies where it is the males who leave their tribe to "marry into" the tribe of their wives. Sons of such societies would be less valued genetically speaking since they would not be around to assist in looking after the children of his siblings.

Another possibility would be societies where much adultery is occurring. In such situations, I cannot be sure that the child of my son would indeed be genetically my grandchild, as my son could have been "cuckolded". My daughter-in-law could have slept with someone else and hoisted the seed of that coupling onto my unsuspecting son! However, regardless of how adulterous a society becomes, I can certainly be sure that the child of my daughter is genetically my grandchild. Why? Because the sperm could have come from anywhere (not necessary the husband) but the egg never left the body until the baby is out of the oven.

Whether my theory is sound would need ultimately further anthropological studies to verify. Nonetheless, following from the previous para, it leads me to postulate why, homosexuality may appear to be becoming more "rampant" in modern times, especially in increasingly urban societies, over and on top of the fact that expression of the self is becoming more accepted. We are increasingly living in a society which may create the situation of greater (genetic) value of daughters over sons. For one, women, with increasing "power" in relationships so to speak, are increasingly more adulterous than before. In addition, with relationships becoming increasingly a series of serial monogamies, the "loyalty" of the biological father may be increasingly diminished. Could such conditions similarly drive up the chances of women giving birth to homosexual sons? Perhaps there are some truths to the now-demonized theory of absent fathers and overprotective mothers?

(Anyway, just want to point out that even I felt that my last para may be pushing the limit of credibility, but just wanted to throw out a wild theory for consideration. :-) )