In the late 1960s, when Masters and Johnson began looking for teams to train as sex therapists, Dr. Julius Fogel and Marguerite Fogel seemed a natural choice. He was both a psychiatrist and a gynecologist. She was a licensed psychologist with experience in marriage and family counseling. And there was a certain appeal about a husband and wife combination.

After several interviews with the staff at the Masters and Johnson Institute, however, the Fogels decided the St. Louis training was not for them.

Almost 15 years later, the Fogels now direct their own sex center. Officially begun in March of last year, the Human Sexuality Institute employs six therapists, including the Fogels, and retains both a urologist and an endocrinologist as consultants.

Generally, the typical treatment program consists of one, hour-long session ($45) per week for approximately 14 weeks. At the first session, clients are asked to complete several questionnaires dealing with medical history and the history of the relationship. The therapist also raises questions about the specific nature of the sexual complaint.

"Believing that no one treatment approach is suitable for all," says its brochure, "we initially spend several hours assessing the needs and life style of each client."

"People come in feeling chaotic and self-conscious at first," says staff therapist Nancy Dickinson. "But once they talk through their problem, describing it in their own words, the tension eases."

No surrogate partners are used. Although surrogates can be helpful in cases where the client has no mate, surrogates invite too many legal problems, says Dickinson. "The veiled phone calls we get asking 'What kind of therapy do you do?' " she says, "usually mean 'Do you treat VD' or 'I'm looking for a surrogate.' "

Nor do clients perform in front of the therapist. "Everyone who comes in here thinks that's what happens," says Dickinson, "but it's just not so." Couples are given specific conditioning exercises for the privacy of their own bedrooms.

At present, the Human Sexuality Institute is not as formidable as its name might imply. With no lab of its own and with offices divided between two locations in the city -- 2201 L St. NW and 2948 Brandywine St. NW (in the lower level of the Fogels' home) -- it has started out on a modest scale. Current cases number 60.

Eventually, however, Julius Fogel hopes the Institute will have a "building of its own and an active, working research group." He has established the non-profit Human Sexuality Research Foundation, which recently began its first research project in conjunction with the National Institute of Mental Health.

For a register ($5) of other certified therapists, interested persons may write the American Association of Sex Educators, Counselors, and Therapists, 600 Maryland Ave. SW, Washington, D.C. 20024.