(CNN) -- Dr. Irwin Goldstein isn't squeamish about describing operations on private parts. He remembers, for instance, that he performed his first penile implant on a patient in 1976. "I just did one yesterday," he added.
Goldstein, 63, director of San Diego Sexual Medicine and director of sexual medicine at Alvarado Hospital, has had a long career providing medical help to those with sexual problems. He has worked on understanding the physiology of the male erection, and has played key roles in the development of drugs for both male and female sexual dysfunction.
"If there's anyone who had put sexual medicine on the map in the last decade, it was Irwin Goldstein," said Abdulmaged Traish, professor of biochemistry at Boston University School of Medicine, who worked with Goldstein for 20 years.
During his career, Goldstein has treated many patients for problems that used to be poorly understood and highly stigmatized -- though much work remains, both in conducting research and removing shame.
"Helping people, now both men and women, with getting their sexual lives in order, and getting that joy from them -- smiling and hugging their partner -- there's nothing like this field," Goldstein said. "It's truly the most amazing experience to be involved in all of this."
Goldstein was recruited to play hockey at Brown University, and stayed on the ice all four years while studying electrical and biomedical engineering. He met his wife there, and she followed him to Montreal, where he attended medical school at McGill University.
In one of his rotations, he remembers a patient coming into the operating room with urinary retention, screaming in pain. The doctor called for the "urology consults," and a happy-looking group of experts came to assure the patient that they would relieve his pain using a catheter. The procedure was successful, and convinced Goldstein that he wanted to become a urologist.
"You can actually have fun and take care of people and do procedures -- it seemed like what I wanted to do," Goldstein said.
He moved to Boston University School of Medicine and, in the 1970s, met his mentor, Dr. Robert Krane. Krane had just learned how to perform surgery on men with erectile dysfunction, using a silicon implant.
"The word 'impotence' wasn't widely used. It was really a (psychological) thing at the time," Goldstein said. "Medical doctors didn't get much involved. There wasn't really thought to be an organic, physiologic basis for this."
Before learning about the penile implant, Goldstein had no intention of going into sexual medicine. But seeing patients' angst, humiliation and frustration before the procedure, and their happiness afterward -- in addition to their partners' glee -- made Goldstein see sexual medicine as an exciting field.
Goldstein has always been "wide-eyed" and "fascinated" with his interests, said his wife, Sue Goldstein, program coordinator for San Diego Sexual Medicine.
"I fell in love with the little boy in him," she said. The couple has three children.
Sexual medicine, meanwhile, continued to emerge as a field during the 1970s.
In 1973, a Czech doctor named Dr. Vaclav Michal first described a procedure for treating erectile dysfunction. It involved taking a stomach artery that fed the abdominal muscle, harvesting it, repositioning it to the base of the penis and connecting it through a penile artery. Unlike the penile implant, the procedure did not involve a prosthetic device.
Michal taught Goldstein how to do this procedure when he visited the United States in 1983.
"The penile bypass surgery was something that has really sort of enlightened me, and I've taken real fascination with, and I've now done 1,500 of these procedures," Goldstein said.
It's not just aging men who are have trouble getting erections. Goldstein has seen many young, otherwise healthy patients injured in sports such as as cycling. He recently saw the condition in a 23-year-old patient who fell on his crotch while skiing.
By the 1980s, for the first time in history, an injectable drug became available to help men have erections, giving them a pharmacological solution to erectile dysfunction. In addition, when patients came to Goldstein for testing, they could be studied in the erect state.
"It opened up Pandora's box in the context of, we now had therapy, we now had diagnostic information, we can now better understand the process of penile erection and its complexity," Goldstein said.
What's in an erection
International meetings began to take place to discuss such advances. Goldstein and Krane held such a meeting in 1988, calling themselves the International Society for Sexual Medicine. The organization then started a journal, the Journal of Sexual Medicine. Goldstein became editor in 2003, a position he still holds.
Goldstein took a truly interdisciplinary approach to the subject of sexual medicine, bringing together clinicians and molecular biologists, Traish said. Beyond sex therapy, said Traish, Goldstein wanted, "research, research, research."
When Goldstein first became interested in sexual medicine, the medical field's understanding of the erection was primitive. He and colleagues wanted to know: What was the chemical responsible for the erection?
The answer: Nitric oxide. It's a gas that sounds a lot more sterile than sexy, but it's the biochemistry of an erection -- the chemical is released when a man is sexually stimulated.
In 1991, Goldstein and colleagues published a study in the Journal of Clinical Investigation showing the role of nitric oxide in the erect penis. Independent groups followed with more studies showing the same thing.
This insight led eventually to the advent of Viagra as a drug for erectile dysfunction.
"Viagra takes the fact that when you sexually stimulate, you release nitric oxide, and then downstream, if you block a specific enzyme, you can encourage the same sort of response that you would get with the injection of the drug" that came out in the early 1980s, Goldstein said.
The 'nuclear bomb of sexual medicine'
Injections and penile implants were available, but few men were taking advantage of them, Goldstein recounted. A safe, effective pill would be a total game-changer, he thought.
This came in the form of a drug called sildenafil citrate, originally studied for high blood pressure and angina, or chest pain. It turned out the drug, invented by British Pfizer scientists Peter Dunn and Albert Wood in 1989, wasn't successful as a heart medicine, but clinical trial participants reported increasing erections. The patent was filed in 1994.
Goldstein and others, meanwhile, were refining their understanding of the physiology of the erection. They became involved in testing the drug as a treatment for erectile dysfunction. Goldstein was the lead author of a New England Journal of Medicine paper that introduced the drug to the rest of the world -- first marketed as Viagra (there are now other versions available).
Viagra was probably "the nuclear bomb of sexual medicine," Goldstein said. It was the first time there was a noninvasive solution to impotence, which had been thought of for so long as an inevitable part of aging.
"This was more or less the dream of humankind from caveman forward," he said.
What about women?
Goldstein began to receive "gazillions of calls" about getting Viagra. Surprisingly, however, the majority of calls were from women who wanted help with their own problems: lack of arousal, vaginal dryness, inability to have an orgasm, pain during intercourse.
Initially, Goldstein told them to call their gynecologists, believing that the field of gynecology was studying how to treat sexual dysfunction in women the way urology was in men.
But many women called back and told him this was not the case.
In 1998, Goldstein and colleagues opened up their sexual medicine clinic to women. "We became overwhelmed," he said. They also started a women's sexual health society, which became part of the Journal of Sexual Medicine as well.
There is no drug approved by the U.S. Food and Drug Administration for the treatment of female sexual dysfunction. A 2008 study found that women taking antidepressant medications called serotonin reuptake inhibitors saw some benefit from Viagra, but these findings have not been shown in the general population.
Women may soon have options, however. Goldstein has been collaborating on the trials for flibanserin, a drug studied for hypoactive sexual desire disorder. Like Viagra, it originally had a different target: depression, but was found to be more effective as a treatment for sexual dysfunction.
In March, a new drug application was submitted to the FDA; the agency has until September to make a decision, Goldstein said. (There are other competing treatments for low female sex drive in the works: Drugs similar to each other called Lybrido and Lybridos, a gel called LibiGel, and a drug called Bremelanotide.)
"2013 is the year of the woman," he said.
A field of its own
Goldstein moved from Boston to San Diego in 2007 to establish San Diego Sexual Medicine, a 6,000-square-foot facility with a sex therapist, physical therapist and a full clinical research facility where scientists study sexual dysfunction. He didn't want it to be part of a urology department; he believed it deserved its own distinction.
"We believe that sexual medicine is an equal form of medicine," he said. "We study and diagnose and treat as you would an arm, a leg, a liver, a kidney, a spleen, a pancreas -- we are just upfront with it."
You can also buy sex toys and aids at Goldstein's facility. He compares these tools to hearing aids for people with hearing problems, as they are strategies for "a more meaningful, full experience."
Many medical school students never learn how to treat sexual problems, he said, and plenty of doctors don't want to touch the subject, either. Goldstein now teaches students in each year of medical school.
Recently, he recounted, a patient told him when she complained to her doctor about pain during sex, she was told, "go on vacation, have a glass of wine. It will definitely work for you." The woman said she received no evaluation or exam, and left the doctor's office in tears.
There's an important distinction, Goldstein said, between sexual medicine and other fields: It's left up to an individual whether a "condition" is actually a "problem." Goldstein and colleagues don't impose their view of an ideal world on patients -- that everyone should have sex every day, for instance.
If people have sexual dysfunction but don't want to pursue treatment, and are content otherwise -- perhaps by pursuing hobbies, holding hands with a spouse and playing with grandchildren -- that's fine by Goldstein.
On the other hand, if a person is bothered or distressed by a sexual problem, Goldstein is happy to help.
"My nametag says 'Irwin Goldstein, physician,'" he said. "It says 'sexual medicine.' I am living my dream right now."