Letter: Nothing new in predicting sexual orientation

Sir: I am prompted to write in response to the woolly analysis presented as wise and considered opinion in your leading article ('Gay genes do not exclude choice', 16 July). No distinction is made between sexual orientation and sexual behaviour. It goes without saying that the latter is always subject to choice and judgements on consenting sexual behaviour belong in the realm of morals.

Sexual orientation is quite another matter. It is easy to measure a person's instinctual and involuntary sexual responses by wiring them to a polygraph, presenting them with erotic imagery and measuring the body's level of sexual arousal in response. This technique will allow scientists to ascertain exactly how strongly particular genes predetermine their bearer's sexuality, independent of considerations of lifestyle, behaviour or an individual's self-conception.

The sexual orientation of children as young as two and a half years has been determined in this way in research conducted at the Institute of Sexology in Indiana, and has thereby shown it to be fixed even at that age, and certainly beyond the individual's choice or control. Hence the indefensibility of discriminating against anyone on grounds of sexual orientation per se should be well established by now, and the fact that orientation may be under genetic control does not really have any new ethical or legal implications.

Yours faithfully,

P. RICHARDSON

Cambridge