An electronics technician who was dismissed from his job at the Central Intelligence Agency last May after voluntarily disclosing that he is a homosexual filed a lawsuit in U.S. District Court yesterday seeking reinstatement and back pay.

The former employe, identified in court only as "John Doe" because of his prior undercover work with highly classified information, contends in the lawsuit that the CIA told him that his homosexuality posed a "security threat," but refused to give him any further explanation.

The man, who had worked for the CIA since 1973, contends that since he has acknowledged to the agency, his family and friends that he is a homosexual, he will not be subject to blackmail or other pressures concerning his sexual orientation. The lawsuit said that lie-detector tests given by the CIA supported Doe's statements that he had not disclosed classified information to homosexual partners and had not had sexual relations with foreign nationals.

The man also contends that he was subjected to far greater scrutiny by CIA officials than heterosexual employes whose conduct--such as extramarital affairs--could pose a security threat.

The lawsuit, filed on behalf of the homosexual by the American Civil Liberties Union Foundation, contends the CIA told Doe that if he should seek a security clearance for a new job, the agency would inform the prospective employer that he was a security risk because he was homosexual.

The man contends that the agency violated its own regulations by failing to provide him with a statement of reasons for his dismissal and give him 10 days to respond.