Gay markers

The link of male homosexuality to q28 gene on the X chromosome was recently reinforced by scientists, exactly 2 years after the first evidence in its favour was produced. After studying a sample of 33 pairs of homosexual brothers, a team led by Stacey Cherny in USA has now reported conclusively that a majority of gays share this gene. However, its presence has been found to be negligible in 36 pairs of lesbian sisters studied by the scientists (Science, Vol 268, No 5217).

Meanwhile, a study on 5,000 same-sex twins, conducted by Australian researchers established that for males, homosexuality is 50 per cent heritable while for females the figure is considerably low.