An examination of family pedigrees revealed that gay men had more homosexual male relatives through maternal than through paternal lineages, suggesting a linkage to the X chromosome. Dean Hamer found such an association at region Xq28. If male sexual orientation was influenced by a gene on Xq28, then gay brothers should share more than 50% of their alleles at this region, whereas their heterosexual brothers should share less than 50% of their alleles. In the absence of such an association, then both types of brothers should display 50% allele sharing. An analysis of 40 pairs of gay brothers and found that they shared 82% of their alleles in the Xq28 region, which was much greater than the 50% allele sharing that would be expected by chance. However, a follow-up study by the same research group, using 32 pairs of gay brothers and found only 67% allele sharing, which was much closer to the 50% expected by chance. Attempts by Rice et al. to repeat the Hamer study resulted in only 46% allele sharing, insignificantly different from chance, contradicting the Hamer results. At the same time, an unpublished study by Alan Sanders (University of Chicago) corroborated the Rice results. Ultimately, no gene or gene product from the Xq28 region was ever identified that affected sexual orientation. When Jonathan Marks (an evolutionary biologist) asked Hamer what percentage of homosexuality he thought his results explained, his answer was that he thought it explained 5% of male homosexuality. Marks’ response was, “There is no science other than behavioral genetics in which you can leave 97.5% of a phenomenon unexplained and get headlines.”
Conclusion… the media (and many in society) will get behind anything even if there is only a 2.5% chance its being accurate.