Are we born to be gay or is it something that we 'learn'? Is it
nature versus nurture? In the 1990's scientific discussions tried to
confirm whether or not we could be born gay, or at least to have the
tendency attributed to that of our genetic makeup. This all stems
from the 'X' chromosome which, genetically speaking, males receive
from their mother and a 'Y' chromosome from their father. Since homosexuality seemed to be linked with the mother's side of the family , the researchers
centred their studies on the X chromosome.
- The X chromosome debate rose from a study where researchers tried to find a genetic link to homosexuality. William Henry, in an article entitled
Born Gay?
which originally appeared in Time magazine,
reported that a team headed by Dean Hamer at the National Cancer Institute's Laboratory of Biochemistry (NCI) in Bethesda,
USA., studied 76 gay men and found that their families included a much higher proportion of homosexual male relatives
compared to the average national population. For the most part, this disproportion was found to occur on the mother's side of the family. This prompted the researchers to look at the chromosomes which determine gender, namely the X and Y chromosomes.
What the group discovered was that from the DNA studied from 40 pairs of homosexual brothers,
the DNA from 33 pairs shared five areas of genetic material centred around one noteworthy region of the X chromosome. In an article entitled
Embargoed Advance Information from
Science, it clarified that this region, named Xq28, is located on the tip of the long arm of the X chromosome and contains several hundred genes. This similarity in 64% of the test subjects is notable, as Henry
explained, because the gene sequences of the mother's two X chromosomes are highly variable and also the genes between two brothers usually vary greatly. Statistics would state that so much of a similarity between brothers who also share a sexual orientation is unlikely to be a simple chance occurrence.
He goes on to say: "The fact that 33 out of 40 pairs of gay brothers were found to share the same sequence of DNA in a particular part of the chromosome suggests that at least one gene related to homosexuality is located in that region."
Of the studied brothers, homosexuality was the only trait that all of the brothers shared; they didn't have the same eye
colour or shoe size and they were all completely diverse except for sexual orientation. He quotes Hamer as saying, "This is by far the strongest evidence to date that there is a genetic component to sexual orientation. We've identified a portion of the genome associated with it."
The study also attempted to explain why homosexuality does not simply genetically die out, when it might if it were simply hereditary. The answer is that the gene can be passed along through heterosexual females who carry the gene but which may not cause these women to be homosexual. They could then pass this along to their children who may exhibit a homosexual orientation.
 Since the original 1993 study, additional research has been done by the same research team at NCI. In an
article which originally appeared in the Seattle Times on
31 October 1995, it was reported that Hamer and his team conducted an additional study of 32 gay brothers in which his findings matched those of his previous studies.
As per Hamer "(This) firms up the connection between genes and their association with gay men."
This second study also included heterosexual brothers and Hamer
concluded that straight sons received one copy of the X chromosome while gay sons received the other X chromosome carrying the specified gene sequence.
Critics of the X chromosome theory point out inadequacies of the study. The only research team to confirm the original 1993 results was the same team of scientists, Hamer and his team at NCI. The same team also had been optimistic on their initial findings on locating similar gene correspondencies in lesbian X chromosomes; however, they were not able to find any such likeness.
Dr Elliot Gershon, chief of the clinical neurogenetics branch at the National Institute of Mental Health, states "one should be skeptical of any such linkage until other laboratories have confirmed it." Additional research is being done by teams at the University of Colorado at Boulder and the Whitehead Institute for Biomedical Research in Cambridge,
Massachusetts. Their findings will eventually concur or disagree with Hamer's
findings.
Another reason for not completely accepting Hamer's discovery is the fact that he has not yet been able to
localise the gene which may be causing homosexuality. Hamer's paper is
careful to not state that he has found a "homosexual
gene"; they merely have an area in the gene sequencing which appears in many of his test subjects.
Hamer still has no clue where the gene is exactly or what it does. Of the identified region in Xq28 the gene they may be looking for is in a sequence approximately 4 million base pairs long and may be only one of hundreds of genes in that particular area. Researchers are working now to specifically identify all the genes in that area but that may still take some time.
So the debate still rages on. Whatever our
sexual orientation though, it's best that we just accept who we are
and fulfil our lives the best way possible.
More information on this subject may be found here
within this Web site - It's all in your genes Part
2
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GayCruz
Coming Out -
Born to be Gay?
