In 1993 the announcement of evidence for a "gay gene" on the X chromosome generated enormous publicity. In contrast, the recent publication of research failing to support this link has been greeted with silence by the news media. Rice and colleagues [Rice, G. et al. (1999) Science 284, 665-667 (Abstract)] studied 52 homosexual pairs of siblings to see if any shared alleles in the relevant part of the X chromosome more often than would be expected by chance. They didn't.
Comment: The authors of the original paper have criticised the new research for not restricting the study group to families where there was an indication of X-linked inheritance of homosexuality, that is transmission of the trait via the mother. They say that the lack of this criterion would tend to obscure a true X-chromosome linkage operating in a subset of homosexuals. Only further research will show whether this criticism is justified, but for the present it seems that in the homosexual population as a whole, inheritance of a homosexual tendency via the X chromosome is not a major factor. The magnitude of any genetic effect on homosexuality remains uncertain.