Forget the cliches, the snickers and the dirty jokes. Forget the salacious stories about surrogate partners. Forget the myths of group sex.

And yes, forget the idea of disrobing and having your lovemaking technique analyzed the way a golf pro would pick apart your swing.

Sex therapy today is a rapidly growing specialty that is finally gaining respectability after being the often-ridiculed black sheep of psychotherapy. Like its parent discipline, however, sex therapy is being shaped by evolving notions -- including the idea that health concerns of the body are inseparable from those of the mind. Almost everyone experiences a brief sexual problem at some time or other. Parents of newborn infants may find that their round-the-clock schedule leaves little time for sleep or for sex. People under stress at the office often report that their desire for sexual intimacy decreases with their workload. Just having a bad cold or a case of the flu can quickly dampen sexual desire or interfere with the ability to experience sexual pleasure. Even the weather affects the sexual drive.

But some Americans experience sexual difficulties for months and even years. Estimates are that "50 percent of all adults will suffer from a significant sexual dysfunction at one time during their lifetime," says Dr. Helen S. Kaplan, director of the human sexuality program at New York Hospital. The causes of sexual problems are almost as diverse as the thousands of individuals who suffer from them. Medical problems, marital strife, job stresses, business reverses, physical ailments and mental illness -- particularly depression -- can all prompt sexual difficulties.

Yet one overriding message is clear: In the 25 years since Dr. William Masters and his colleague Virginia Johnson first pioneered sex therapy techniques, numerous studies have shown that the therapy works, regardless of the problem's origin. After years of believing that sexual problems arose from deep-seated, unconscious anxieties about such things as castration, penis envy, unfulfilled Oedipal yearnings and Electra conflicts, sex therapy now recognizes that sexual difficulties are typically learned responses or habits that can be unlearned -- often in weeks or months.

A variety of studies show that between 50 to 90 percent of the people who undergo sex therapy with reputable practitioners are successfully treated. And for certain disorders, such as premature ejaculation, the recovery rate is almost 100 percent.

"That's about as dramatic an advance as the introduction of penicillin," says Dr. Robert Kolodny, director of the Behavioral Medicine Institute in New Canaan, Conn. and co-author with Masters and Johnson of the new book, "Sex and Human Loving."

Yet sex therapy offers no instant, magical cure. It takes commitment and hard work by patient and therapist alike, just like psychotherapy. It also takes a willingness to confront sexual problems -- a prerequisite that some people find too painful to do.

In addition, sex therapy still suffers from a tarnished image -- one that's linked to the lack of quality control over most sex therapists in the United States. Since no state or region offers licensing or certification, literally anyone can call himself or herself a sex therapist and go into practice -- from the massage parlor operator to the psychiatrist with three years of post-graduate sex therapy training.

"When it comes to sex therapy, it is the consumer beware," says Dr. Teresa Crenshaw, president of the American Association of Sex Educators, Counselors and Therapists (AASECT).

Yet a growing number of training programs affiliated with medical schools and universities throughout the country are working to change this image. With this change has come a major alteration in the way sex therapy is practiced. efore 1970, anyone with a sexual problem generally faced one-on-one treatment, usually with a psychiatrist. Therapy lasted for years, yet recovery was often uncertain.

Today, however, sex therapy is typically for a limited time only -- usually six months or less -- and sometimes for just an intensive two-week period. It is most likely to involve a couple, (rather than just one individual), who meet with a two-person psychotherapist team, rather than one psychiatrist. And it is far more likely to rely on several schools of thought, particularly behavioral and cognitive therapy, rather than adhering solely to traditional Freudian psychoanalytic concepts.

Sex therapists now are more likely to be one of several types of health professionals rather than a classically trained psychoanalyst. Among the specialists who take additional training to become sex therapists are clinical psychologists, physicians (including urologists and obstetrician/gynecologists) social workers, nurses, family therapists and pastoral counselors.

Also new is the ability of sex therapists to diagnose medical causes of sexual problems unheard of 20 years ago. As a result, treatment of sexual dysfunctions "has changed just remarkably in the last quarter century," says Dr. William Masters, cofounder of the Masters and Johnson Institute in St. Louis. "The main change is that people are becoming more and more comfortable about going for help.

"When we first started offering therapy, the average age of patients was in the mid-40's. Now it's in the mid-30's. People are more aware, and they are not waiting so long to come in for help."

But perhaps because of its youth -- or its sensitive subject area -- sex therapy remains one of the most misunderstood therapies around. Contrary to popular myths, sex therapy patients don't undress and perform sexually for the therapist's analysis and treatment. Instead a visit to a sex therapist is virtually indistinguishable from a consultation with any other type of therapist.

"Many people think that sex therapists deal with sexual gymnastics, 10 new positions and G-spots," says AASECT's Crenshaw. "That might be more titillating, but it's really the smallest part of what we do."

Instead sex therapy is based upon establishing communication -- and intimacy -- between loving partners. "Sex therapy is basically intimacy therapy," says District physician Armando DeMoya, who with his wife Dorothy, was one of the first six couples trained in sex therapy by Masters and Johnson.

People who undergo sex therapy practice the skills their therapist recommends in the privacy of their own bedrooms, with their own spouses or partners.

"Most sex therapy is done in couples," says Dr. Barry McCarthy, a clinical psychologist who practices sex therapy in the District. This idea derives from a Masters and Johnson concept that sex therapy is aimed at placing no blame. It is not the individual who receives help, but rather the couple and the relationship.

The best candidates for sex therapy are couples who "have a committed relationship," says McCarthy. They also have "a specific sexual dysfunction and are harboring myths about sex therapy, but they want to work it their problem out."

The worst choices for sex therapy, McCarthy says, are those couples who "are just about to see the divorce attorney." They seek help only as a last resort before taking steps to dissolve their marriage. Filled with anger and resentment, these couples often have great difficulty working out their problems in sex therapy.

Nor is sex therapy limited to the heterosexual world. The treatments are typically available to couples of any sexual persuasion with one limitation -- they must be a committed couple.

"Gay men have just as many sexual problems as straight men," says McCarthy. And lesbians also frequently seek help.

Yet despite the myriad advances in the field, many people are simply too embarrassed to seek help. Others fear the stigma of admitting a sexual problem. Sex therapy today is struggling through the same metamorphosis that psychotherapy went through a decade or two ago.

Few patients undergoing sex therapy will discuss their treatment with friends or relatives, the way they might talk about their psychotherapy at a cocktail party or over lunch, McCarthy says. Fewer still are willing to offer referrals to their sex therapist the way they might tell a friend about a well-qualified psychotherapist.

"People used to slink in the front door and out the back for treatment," says AASECT's Crenshaw. Today they are more apt to sit unashamed in a waiting room, she says, noting however, that "we're just coming out of the era of dark glasses and trench coats."The change is still occurring slowly by all accounts. Some sex therapists in large metropolitan regions such as New York City report major changes in attitude. But most Americans still shy away from discussing sexual problems.

In a nationwide survey of impotence, Public Opinion Research Corp. of Princeton, N.J., found that almost half of 1,000 men and women polled refused to discuss the subject. Those who would discuss it often confused impotence with infertility. Some 14 percent of people polled mistakenly thought that impotence meant the inability for a man to have an orgasm and 5 percent of those polled had no idea what impotence meant.

For this reason, says William Masters, "sex education is the biggest sexual problem in the United States today."

Health professionals who provide sex therapy also sometimes face problems because of their specialty. In certain areas of the country, "there is a stigma not just for the patient but for the therapist as well," says the District's McCarthy.

In general, sex therapy begins with a comprehensive physical designed to rule out any possible medical problems. At the Masters and Johnson clinic and at the clinic run in Washington by Dr. Armando DeMoya and Dorothy DeMoya, this physical is done with both partners present.

Next comes a sexual history which covers such information as "tracing the sequence of people they have chosen to have relationships with," says Linda Levine, a social worker who conducts special workshops for women experiencing sexual problems. It also includes talking about their own sex education. How did they originally learn about sex? How much of their information is accurate? What kind of sexual relations did their parents have? Sometimes people with sexual problems "are playing out the imprint for intimacy that they learned from their parents," Levine says.

After a close evaluation of this physical and psychological information, sex therapists discuss their assessment of the couple's situation and offer a plan of treatment. The most common sexual problems include: Rapid or premature ejaculation. Estimates suggest this is one of the most common sexual dysfunctions, afflicting from 10 to 30 percent of men. It can be treated successfully by sex therapy in close to 100 percent of cases. Yet Masters and Johnson report that fewer than one-tenth of men with this dysfunction "consider it enough of a problem to seek help." Anorgasmia or orgasmic dysfunction. This condition describes women who have difficulty experiencing an orgasm or who have never had an orgasm. Both conditions can be treated by sex therapy. Retarded ejaculation. This delayed ejaculation appears among men of all ages. Occasional difficulty with ejaculation "is not a sign of sexual disturbance and is often related to fatigue, tension, illness, too much sex in too short a time or the effects of alcohol or other drugs," advise Masters, Johnson and Kolodny in their new book, "Masters and Johnson on Sex and Human Loving." It can also be caused by feelings of not being emotionally involved with a partner, they write. If retarded ejaculation continues, it can cause resentment in a woman for the "sexual demands placed on her by her partner," Masters and Johnson report. Ejaculatory incompetence. This is the "inability to ejaculate within the vagina despite a firm erection and relatively high levels of sexual arousal," according to Masters and Johnson. This problem is infrequent and usually occurs only in men under 35. Impotence. The chronic inability to obtain an erection affects up to one in every 10 men. But "isolated episodes of not having erections (or of losing an erection at an inopportune time) are so common that they are nearly a universal experience," write Masters, Johnson and Kolodny. Thus, a man is considered to have an impotence problem only if erection problems occur in "at least 25 percent of his sexual encounters." Inhibited sexual desire. This is one of the more recently recognized sexual dysfunctions, and some experts estimate it accounts for three of every 10 visits to a sex therapy clinic. Women seem to develop inhibited sexual desire more often than men. It can be caused by physical or emotional problems, ranging from hormone deficiencies to alcohol or drug abuse, kidney failure and severe chronic illnesses. Some 10 to 20 percent of men with the problem have "pituitary tumors that produce excessive amounts of the hormone prolactin," say Masters and Johnson. Most cases of inhibited sexual desire are caused by such things as depression, prior sexual trauma, poor body image, low self-esteem or power struggles within relationships. It can be treated in 80 percent of cases. Vaginismus. In this condition, the muscles around the vagina contract involuntarily in response to penetration. The result is very painful intercourse for an estimated 2 to 3 percent of women. In some cases, vaginismus is so severe that intercourse is impossible. Dyspareunia, a type of painful intercourse. In men suffering from this problem, intercourse produces extreme discomfort in the penis, prostate and testes. In women, intercourse results in burning, sharp or searing pain, or cramping externally, within the vagina or deep in the pelvis or abdomen. This pain can occur at any time during or shortly after sex. Sexual aversion. This severe phobia or irrational fear about sexual activity can affect both men and women. It can produce sweating, nausea, diarrhea or a racing heart beat. Not surprisingly, Masters and Johnson report that people who suffer from this rare problem avoid situations that could lead to sex. Yet studies show that sex therapy can be used to successfully treat these people in more than 80 percent of cases.

However or whenever they occur, sexual problems are worth addressing, experts say. They can be a sign of undetected medical illnesses including diabetes. They can signal problems in a marriage or relationship or point to psychological illnesses such as depression.

"A fair number of people may develop sexual problems as their marriage is ending," says McCarthy. Age also affects sexual functioning. "You can't look and function your whole life like you did at age 20," he says.

In addition, sexual problems "are five times greater in couples with fertility problems," says AASECT's Crenshaw. But which comes first -- the fertility problem or the sexual dysfunction -- is sometimes difficult to tell. In some couples, the sexual problem may be the real cause of infertility. In others, the fertility treatment may result in a temporary sexual problem since their sex life has become a mechanical ritual timed -- not for pleasure -- but to capture the most fertile moment.

Other causes of sexual problems include alcohol or drug abuse, certain high blood pressure medications and heavy cigarette smoking. But like the Freudian saying that sometimes a cigar is just a cigar, it is also true that sometimes sex problems are merely that, sex problems.

"Today, most sexologists recognize that many people with sexual dysfunctions have completely normal personalities, no signs of emotional illness, and simple, straightforward explanations for their problem," write Masters, Johnson and Kolodny.

And sometimes one trip to a sex therapist will assure couples that their problems are not rooted in their bedroom behavior. Some people simply need time together, notes Dr. Patricia Schreiner-Engel, director of human sexuality at New York's Mount Sinai Hospital.

As an example, she points to a couple who came to Mount Sinai for help who had three children, the youngest of whom was severely handicapped. The husband worked nights to make extra money for the family. The wife didn't drive and was isolated in the suburbs trying to care for her children, but felt guilty about all the time that she had to focus on the handicapped child.

"They had a natural response to a very difficult situation," Schreiner-Engel says. "He wanted to connect with her and feel close. She was overwhelmed and depressed and needed support. She couldn't be expected to feel romantic under those conditions. They needed some time away together and some more help around the house. What they didn't need was to think that they also had a sexual problem."

Although it can help in many cases, sex therapy is not a magic cure for all the ills in a relationship.

"When a couple comes in for sex therapy, one of the expectations is that sex therapy will completely change the personality of their partner," says the Behavior Institute's Kolodny. "Sex therapy is not going to do that. It will not transform someone who has no sense of humor into someone with all the opposite attributes.

"It may certainly help people improve certain problem areas of behavior so that lots of couples find that they are better communicators together and are better at solving different kinds of problems. But you're not bringing someone in for a personality change."