BTW, I thought that the huge brothers' DNA study being done at Northwestern by Sanders and Bailey was supposed to have been completed and the results published way over a year ago, but I haven't seen anything unless I missed it. Anyone know what's up with that? They were trying to determine once and for all by amassing a huge sample if Hamer's linkage claims had any validity.

Regarding the condition of CAH--http://www.newscientist.com/article/dn19151-debate-over-gender-disorder-drug.html Concerns about the safety of treatment and the knowledge of the parents involved are legit, but "concerns" from those who think parents have no business caring about or preventing such a condition in their child are the selfish rantings of a political minority. Anyone who'd prevent me from taking action to prevent CAH, (again, assuming it had been deemed safe) would be subjected to fist in his or her face. This reminds me of how some in the deaf community fight against coclear implants in children, maintaining that deafness is not a disability. They can argue whatever they want; it's none of their business what I decide for my child. Perhaps it has happened, but I have never heard those pretty much confined to wheelchairs argue that children born with disabilities that make it difficult to learn to walk not be fitted with devices that enable them to do so.

EW, You get a variety of what seems, at least on the surface, to be conflicting research on the maternal stress hypothesis as it relates to life events: two for example, http://www.jstor.org/pss/3812874 versus http://www.springerlink.com/content/q6q2180250341315/ How hard would it be to collect data from a random sample of women who were pregnant, say, during the Northridge or Loma Prieta earthquakes? Or, if those events are considered too short-lived in duration, what about women who were pregnant during their husbands tours of duty in Viet Nam? Women who were pregnant and living close to the 9/11 attacks have children now approaching 9--are the number of male gender atypical children born to them significantly higher than in the general pop? Trimester of pregnancy would be of interest, of course. It seems there are limitless historical events that could be used for such studies to establish whether a pattern exists or not. One could even collect data from a series of populations of relatively small towns in which stress-causing events took place to see if patterns emerge in the % of homosexual males v. heterosexual males born to women pregnant during those events. Since the immune system is compromised by stress of all kinds it makes sense that atypicalities during pregnancy would occur during such times of high stress, but even the common cold, the flu, and any number of other common infections may have the same effect if any of them strike during a period of important fetal or neonatal development.

I certainly don't doubt that there's a biological root to homosexuality, at least the kind in which a male just isn't turned on by females, and I doubt that other gnxp readers harbor doubts, but the "genetic variation" term is problematic. First, however, the brain scans--If I remember, the Savic/Lindstom sample size was less than a hundred, half heteros, half homosexuals. I do remember that the hemispheric size differences they noted in straight men and lesbian women were "slight" while they said that the hemispheres were somewhat more symmetrical in homosexual men and heterosexual women. Those adjectival describers are hardly strong evidence although even "slight" and "more" symmetrical might be meaningful with a larger sample size and if the "slight" had high predictive value. If it turns out that these brain scans do indeed show structural differences that actually mean something, are these differences directed and established in utero? Or soon after birth? Or, in early childhood? Are they directed by "genetic variation"? Or by some triggering agent(s)? We've still the question of the identical twin concordance rate (isn't it about 45-50%?). In order for the "genetic variation" argument to make sense, you'd have to argue that something is turning off/on a gene(s) in one twin, but not in the other. If so, what? What usually causes such epigenetic occurrences? I have to admit having a big problem with the use of the germ "genetic" since one group seems to use it in one way and other groups in another way. Is it accurate to speak of any such switching on or off as "genetic" rather than as "biological"? For all the studies, I still get the feeling that we are missing the forest for the trees on this one. Or, perhaps it's more accurate to say we are missing the tree for the forest.

"Selective abortion of females is an issue that many American pro-choice activists have tried to avoid. Since they are not on record as fighting this horrifying trend (tens of millions of females aborted in recent decades), they will not be in a strong position to oppose selective abortion of homosexuals. We’ll have to count on the Christian right to oppose such a practice if it ever takes root." A great irony, for sure. Feminists and pro-abortion activists would not be vocal in opposing selective abortion of fetuses that might tend toward being homosexual. It's always amazing when new circumstances make political bedfellows into political opponents very quickly. "In any case, abortion is a less likely outcome that medical intervention in utero to reduce the likelihood of homosexuality." My guess too. Fundamentalists would welcome this, but so too will most people, including the non-observant and the non-believers. "Here’s a prediction: at some point in the medium future American society will be ready to accept homosexual orientation as morally equivalent to heterosexuality; at just about that point, medical intervention will be available. If even a minority of parents take that route, homosexual orientation will begin to decline, as fewer and fewer such individuals emerge from the womb." Growing numbers of people see homosexuality as having a biological basis so they don't see it as a moral failure, I agree; however, this does not mean they view it as a neutral or positive trait. It's definitely not a trait they'd prefer for their own kids. They will gladly opt for medical intervention for their offspring for this as they would for any number of other anomalies or atypicalities.

"Differences in fetal environment from one twin to another can explain the twin disparity. Corpus Callosum atresia is regulated by Testosterone (T). T receptors are also adrenaline receptors, so if one fetus is stressed at the time when the Corpus Callosum is breaking down, then the T doesn’t get through because the receptors are occupied with adrenaline" Yes, levels of stress hormones affect testosterone "baths." I also remember reading that stress increases the permeability of the blood brain barrier--Cochran's pathogen could come into play here. Still, if stress responses are the major cause, one would think that studies would show that there were an unusually high number of births of what turn out to be gay people during historical periods of great stress for a population. I think there have been some such studies and they came up empty.

EW, Thanks for the references. I'll check them out. When I get a chance, I'll see if I can find something more recent and whatever sources I read that referred to older studies. A close friend of my mother and father bore three sons by two different husbands. Two sons are gay--the ones with different fathers. The first son was quite gender atypical as a kid, dressing up in his mom's apparel, complete with make-up, at every chance when he was small. The second son was, as is often said, "all boy." The third son, the one by a different father, is quite a bit younger than the other two, eleven and twelve years younger. He was not gender atypical as we think of it, but he was a kid who seemed to prefer his own company rather than playing too much with others his age, withdrawing into his room to play with all the toys his middle class parents threw his way. This one married, had two daughters, then astounded pretty much everyone by heading for the city and, well, being gay. It's a good example of a familial connection researchers have noted.

"It should not be long however before some genetic variants are discovered that are associated with sexual orientation and these should give clues to the genesis of brain wiring differences between the sexes and how they control sexual preference." Where have I heard this before? If they are going to find something, I'd not be surprised if it was related to the immune system.