Letter: The latest science fashion in genes

Many conditions of complex origin, such as mental illness, have been studied in an attempt to determine an underlying genetic cause ('Nature, not nurture?', Sunday Review, 4 October).

In the 1920s and 1930s the causes of mental illness were thought, especially in Europe, to be genetic and the elimination of 'tainted' strains the best solution. Post-war America favoured environmental causes, including bad child-rearing, as the likely explanation for mental illness. More recently, following failure to identify such causes, the pendulum has swung back in favour of a genetic explanation.

The evidence described by Sharon Kingman is part of the much wider development of scientific thinking about inheritance, and in no way specific to homosexuality. Homosexuals, or any other group, should not have to await the discovery of a gene which determines their condition to be treated as human beings.

Dr Joseph Bray

Department of Psychiatry

University of Leicester