"Of the 40 sets of brothers, 33 shared a set of five markers in the q28 region of the long arm of the X chromosome. The linkage has a LOD score of 4.0, which translates into a 99.5% certainty that there is a gene or genes in this area that predispose males to homosexuality."

Obviously the conclusion that "there is a gene or genes in this area that predispose males to homosexuality." Is based, not on fact, but on the predisposition of the researchers (who are in all probability gay) to defend homosexual behaviour. A more reasonable conclusion would be that the practice of homosexual behaviour eventually changes the makeup of the chromosones. In the case of the remaining 7 sets of brothers, they had, in all probability, not yet engaged in enough homosexual behaviour to cause the observable changes.