Now, we may know why. Andy Coghlan from New Scientist explains: Anthony Bogaert at Brock University, Canada, and his team think that some women who are pregnant with boys develop antibodies that target a protein made by the Y chromosome. Our immune systems make antibodies to recognise foreign molecules, which have the potential to be from dangerous bacteria. But pregnant women sometimes also produce antibodies against fetal molecules — for example, if their fetus has a different blood group. The team collected blood from women, and screened it for antibodies to a particular brain protein that is only made in males.
By Michael Balter Jun. Most researchers who study sexual orientation think that both genetic and environmental factors play a role, but the relative contributions of each remain unclear. A new study of Swedish twins reinforces earlier findings that environmental influences--including the environment in the womb--may play a greater role than genes. Scientists studying complex human behaviors often turn to twin studies.
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Share via Email Genes are far from the whole story. But the scientific evidence for a biological basis for sexual orientation seems strong. Scientific evidence says otherwise.
Killer of Kimberly Proctor denied parole and escorted absences Sexual identity defies a simple, single explanation and even categorization. As such, trying to identify a single cause of sexual identity, genetic or environmental, is not going to be successful. With increasing recognition that people do not fall into binary categories, we can see the limitations of studies that have attempted to answer your question. Nonetheless, the data is useful to look at.
The study clearly links sexual orientation in men with two regions of the human genome that have been implicated before, one on the X chromosome and one on chromosome 8. The finding is an important contribution to mounting evidence that being gay is biologically determined rather than a lifestyle choice. Advertisement The region on the X chromosome picked out by the study, called Xq28, was originally identified in by Dean Hamer of the US National Institutes of Health in Bethesda, Maryland, but attempts to validate the finding since have been mixed. The other region picked out is in the twist in the centre of chromosome 8.
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Measures of sexual orientation, which are free of the limitations of self-report, include genital arousal and pupil dilation while viewing sexual stimuli depicting men or women. We examined these responses in 6 male twin pairs and 9 female twin pairs who reported discordant sexual orientations. Across measures, heterosexual male twins responded more strongly to women than to men.
Some of our knowledge comes from science. Sadly, misunderstandings and misrepresentations of scientific research have been used to encourage people to ignore Scripture, abandon faith and embrace homosexuality as if they have no choice. Misunderstandings and misrepresentation of twin studies has led many people to believe twin studies have conclusively shown that there is a genetic basis for sexual orientation. People who experience same-sex attractions can still make choices.
Print For men, new research suggests that clues to sexual orientation may lie not just in the genes, but in the spaces between the DNA, where molecular marks instruct genes when to turn on and off and how strongly to express themselves. Through the epigenome, the results suggest, some facet of life experience likely also primes a man for same-sex attraction. But they increasingly suspect it is forged, in part, by the stresses and demands of external influences.