London-based gay charity Galop is seeking other men who have had to reveal past convictions for buggery or gross indecency.
The charity is supporting John Crawford, who is fighting to remove a 51-year-old conviction for consensual homosexual sex from his criminal record.
Mr Crawford says he was jailed, beaten and essentially tortured by police to extract a confession from him in 1959, when he was 19.
Although homosexuality is no longer a crime in Britain, he must reveal his conviction when employers ask about his criminal record or when he applies for volunteer positions working with vulnerable clients.
Galop helped Mr Crawford get legal representation and is now looking for others who may have had similar experiences, and who may be interested in joining a potential legal action.
Chief executive Deborah Gold said: “The enforcement of this law is effectively re-criminalising John and others like him, forcing him to repeatedly re-live his worst experiences, and causing him to have to out himself to potential employers.
“Galop demands that the police and the Home Office change the rules so that no one else is forced to suffer in the way that John has”.
Anyone who has been affected is urged to contact the charity on 020 7704 2040.