The discussion surrounding a possible organic cause for homosexuality has been ongoing for nearly seventy years in an on again/off again style of conduct. While the most popular, and generally erroneous notion is that there is an actual gay gene, most theories do not necessarily explore that as an absolute possibility in the sense that most people view it from their limited gleaning of what is present in the media or oddball "Christian Science" organizations like NARTH which have regularly and roundly been criticized for running tests which fail to meet the scientific process or randomly omit data which does not support their own findings. What this article will explore is the most logical and widely accepted theory and research as to a possible organic cause for homosexuality.
Before beginning it is important to understand that while scientists are quick to point out that there has been no discovery of a "special" or separate gay gene which only appears in homosexuals they do suspect that genetics does play a role and that there may very well be some mutability to a gene found in homosexuals. Several studies conducted over the past twenty years which have been vetted and compared independently do seem to correlate to each in these findings.
In the Blanchard and Bogaret test it was found that the chances of a male being born homosexual did seem to increase in accordance to not just their birth order, but more specifically the number of male siblings his mother has previously produced, even when that child is raised apart from that family unit. The findings of this study point out that with each male fetus, a mother undergoes a period of increased immunization to an antigen produced by male fetuses. This antigen is specifically linked to the masculinization of the brain.
In a similar study conducted by Camperio-Ciani, it was noted that male homosexuality is most likely inherited from the mother in part due to the reason cited in the Blanchard and Bogaret study, but also as a part of the natural selection process. They point out that the fecundity of one sex that may be increased by one gene is related to the decrease of the other its fecundity on the opposite sex. The short version in lay mens terms basically states that the more male children a woman produces, the more the body attempts to produce a female offspring to balance the population and vise versa. They then theorize that because the body and brain of the fetus may not be receiving the proportionate amount of hormones for heterosexual development, thus producing a homosexual.
These both in turn relate to the belief that there is in fact a gene that does contribute to homosexuality, but again not in the sense that most organizations portray in order to say it does not exist. The most recent findings point towards a polymorphic gene which means the gene is in flux and can exhibit multiple forms. This is not so far fetched as many pundits present due to the fact that gene mutation is a known and accepted fact of biology. This was most deeply explored in the Gavrilets and Rice study which concentrated solely on the exploration o gene polymorphism in regards to homosexuality.
They began their study in the simplest of forms by examining the simple fruit fly which shares a very high rate of common reproductive and neurological genes with humans. By manipulating one gene in fruit flies they upheld earlier studies that the sexual orientation of a fruit fly could clearly be changed to either, gay or lesbian. As the manipulated gene was one shared with humans, they theorized at least that the same was possible with humans.
Their findings for gene polymorphism that leads to homosexuality are based on two factors which are sexual antagonism and overdominance. Overdominance is the byproduct of phenotypes which come from heterozygous genes to promote genetic variation. It is known and accepted that without genetic variation everyone would be a carbon copy of each other basically. Sexual antagonism traits are those which may be considered advantageous in one sex, but in the other cause homosexuality. As promising as the data is and has been overwhelmingly definitive in lab research, the permission to alter a gene in humans, even slightly, will likely never be granted to try to prove this these theories once and for all.
A second school of thought which in some ways lightly overlaps these studies but is still distinct explores the role of hormones in the fetal period of development. It is known and upheld without argument that hormones determine the physical sex of a child. A fetus undergoes two hormonal washes, if both are predominantly estrogen then the child develops as a female. if the second hormonal was is predominantly testosterone the child develops physically male, aside from somewhat rare anomalies like the case of intersex persons which is about a 1 in 2,000 occurrence.
The general idea is that if the second hormonal wash strays too far from the norm or the hormones are "absorbed" in a a manner which is not proportionate between the body and brain, that development between the two is inconsistent. In effect a male bodied child may have received enough testosterone to develop in that physical manner, but not enough to cue the brain to follow suit and vise versa in the case of lesbians in that they receive a tad too much testosterone which is "absorbed" by the brain and cues male brain pattern development with a physically female body. As all human life begins in the female form and then has the potential to develop into a male form this theory has long been dubbed as quite logical and even probable, but gain testing on humans has and likely never will be allowed to uphold the theory.
In short there are two very logical and consistent theories for an organic cause in regards to homosexuality. As there is no "smoking gun" gene and the FDA nor any responsible agency of the like will ever endorse the manipulation of genes and hormonal washes in fetuses these will likely never be allowed to advance beyond anything but theory even when they have been proved as true in studies of creatures with similar genetic makeups of humans and various animals in research facilities. Those that are invested in believing homosexuality cannot be organic will continue to argue that is different because humans are not animals (which they in fact are) or that humans are special, which in the animal kingdom they really are not. Regardless of their demands for proof that they government will likely never allow to be found on moral and ethical grounds surrounding the right to alter a humans basic make up in the name of science, everything that has been found to this point through reputable non-biased research facilities says that yes there is an organic cause of homosexuality.