Thomas L. Doerr was an American gay activist. In 1970, he introduced the lambda symbol into the gay rights movement when the image was used to represent the political work of the Gay Activists Allianc… - download at 4shared. Thomas L. Doerr was an American gay activist. In 1970, he introduced the lambda symbol into the gay rights movement when the image was used to represent the political work of the Gay Activists Allianc… is hosted at free file sharing service 4shared.