Obituary: Kurt Freund

Kurt Freund was a pioneer in the field of human sexual arousal. His ground-breaking research in the 1950s led to the development of phallometric testing and he was one of the first to argue that homosexuality was not a pathological condition that should be treated.

Freund's theories contributed to the decriminalisation of homosexuality in his native Czechoslovakia and to its removal in 1973 from the American Psychiatric Association's listings of psychiatric disorders.

"In the 1960s, for example, when virtually all psychologists and psychiatrists agreed that homosexuality was caused by early childhood experiences, he was already arguing that the data more strongly suggested prenatal biological influences," says Ray Blanchard, head of the Sexology Program at the Clarke Institute of Psychiatry in Toronto, where Freund worked from 1969 to his retirement in 1995.

However, it was his work on deviant sexuality for which he was best known. As a researcher from 1945 to 1968 at the Psychiatric Research Institute of Prague he developed a device that, like a lie detector, could reveal more about a man's sexual proclivities than he might willingly reveal. In the test, which is often used to assess paedophiles and other male sex offenders, the penis would be put into a sealed glass tube and the subject shown pictures of children as well as adults. The displacement of air indicated an increase in penile volume which researchers could then match against the images to see which had elicited the greatest response.

Freund became convinced that sexual orientation is set at some point in development and that attempts to alter sexual orientation by means of behaviour therapy or psychotherapy were futile. Instead, he advocated that the treatment of child molesters focus on teaching how to control their impulses despite their preferences.

Freund was not simply a researcher who coldly relied on empirical data. "He was always mindful of the victimisation of children," said Dr Stephen Levine, of the Case Western Medical School in Cleveland. "He was highly mindful that there was some sort of abnormality in a man who victimised children, and he wanted to study this in the hope of defining the sub- types of child molesters to help devise a means of prevention, as well as help the men, who often lead tortured lives."

A graduate of Charles University in Prague, Freund lost most of his family in the Holocaust. Much of his pioneering work was conducted while he was based in Prague from 1945 to 1968, when he fled the country after the failed revolt against Communist rule. He continued his research into homosexuality in Germany and later in Canada, where he remained until he committed suicide whilst suffering from advanced lung cancer.

Kurt Freund, sexologist: born Chrudim, Bohemia 17 January 1914; married (one son, one daughter); died Toronto 23 October 1996.