History Reads is a weekly series featuring work from Team History, a group of experts and influencers, exploring history’s most fascinating questions.

Four years of work, all for naught.

That’s what a team of Pfizer chemists working in southwest England in the early 1990s was coming to conclude about sildenafil citrate, a pharmaceutical compound they had been developing as a possible treatment for chest pain and high blood pressure. Test results for its effectiveness were not looking good. The project teetered on the brink of failure. Then, just as it appeared Pfizer was going to pull the plug, something happened that would earn the company billions of dollars, impact countless lives and upend cultural norms the world over: A few study participants reported that the drug, unexpectedly, was giving them more erections.

The project got an immediate lift.

Combining this finding with new information available from recent studies on the biochemical process of male arousal, the lab soon confirmed that while sildenafil did little for hypertension or angina, it did help the blood vessels in the penis dilate more easily, producing an erection if a man becomes sexually aroused. Some early study participants enjoyed the effect so much, they didn’t want to return unused samples of the drug when the trials ended.

Just a few years later, in March 1998, the Food and Drug Administration approved sildenafil—under the brand name Viagra—to treat erectile dysfunction. Arriving two months after the Bill Clinton–Monica Lewinsky scandal thrust oral sex and semen stains into the national conversation, the drug underscored a fundamental tension in American culture: Everyone was desperate to talk about the taboo topic of sex.

Viagra’s arrival, now 20 years ago, became a watershed moment for men. Previously, the only options for dealing with erectile dysfunction involved treatments that were either shamefully seedy or uncomfortably invasive. The drug also ignited something of a sexual revolution—albeit one with a complicated legacy. Because even as it liberated men from the stigma surrounding erectile dysfunction, it reinforced a very specific, limiting version of sexuality that persists to this day.

VIDEO: MODERN MARVELS: Viagra. A look at how the popular erectile-dysfunction drug works and why pharmaceutical companies are rushing to create alternative versions.

I remember that moment in history well. Initially, media coverage of the new wonder drug reflected America’s competing attitudes toward sexuality: feverish and prurient, scandalized and eager, obsessed and embarrassed. Within a year on the market, Viagra had generated about a billion dollars in sales and appeared on the cover of Time magazine.

Along the way, Pfizer made some canny marketing decisions. The name—a combination of “vigor” and “Niagara Falls”—had been floating around the company for a while, just waiting for the right product. And instead of saying the drug-treated “impotence”—a word that connotes failure—Pfizer billed it as an aid for “erectile dysfunction,” a much more clinical term, one that implies an isolated problem instead of defining a man’s entire persona.

At first, federal regulations prevented Viagra commercials from being run before 11 p.m.—a problem, since much of the drug’s target audience had already gone to sleep. And because the ads had to talk about sexual performance without using the word sex, those first commercials were tame, featuring a wholesome couple wearing visible wedding bands. The implication? Viagra wasn’t a “sex pill,” but a couple’s aid, amenable to America’s puritanical legacy: Since sex is dirty, you should save it for the one you love.

Soon, the stigma began to evaporate—or at least to evolve. After the 74-year-old former presidential candidate and prostate-cancer survivor Bob Dole told TV host Larry King he’d participated in Viagra’s trials, he signed on to appear in an ad campaign. A year after the drug was approved, it became the subject of a Sex and the City episode. No longer shrouded in mystery and pain, erectile dysfunction became part of a broader societal discussion, from the barber shop to late-night TV monologues. The word “Viagra” even entered the cultural lexicon, signifying a catalyst to massive success—as in “That new quarterback has been like Viagra to the team.”

The timing of Viagra’s debut couldn’t have been better, of course, with the first wave of the massive Baby Boomer generation just entering their 50s. A 1999 University of Chicago study found that men between the ages of 50 and 59 were three-and-a-half times more likely to suffer from erectile dysfunction than men aged 18 to 29, and many more would experience other changes in their erections as they aged. Common medications for the over-50 set—for prostate issues, blood pressure, diabetes and depression—also contributed to male sexual performance issues. For the 1960s “youthquake” generation that in many ways, resists going gently into their dotage, the little blue pill has offered the promise that, in at least this one way, they could stay forever young.

As one of the first drugs advertised directly to the consumer, Viagra became a legend in doctors’ offices. An initial shortage created a small frenzy. Many physicians had to open weekend consultations, with 10-minute sessions, to give out samples. Some patients arrived wearing disguises and giving false names to hide the fact that they were seeking treatment for erectile dysfunction. One office referred to the drug as “Vitamin V” to help patients avoid embarrassment. A salesman recalled to Bloomberg that he felt like a “rock star.” “Never before, and probably never again,” he said, “will anybody get a standing ovation in the waiting room.”

Talk about a turning point. Until Viagra, the possibilities for treating ED ranged from dubious to downright scary. Ancient Greeks and Romans ate snakes as well as the genitalia of goats and roosters; Romans also advised wearing “the right molar of a small crocodile” as a talisman to guarantee erections. One 13th-century monk advised men to roast a wolf’s penis, chop it into small pieces, and eat a small portion for instantaneous arousal; European astrologers during the Renaissance and the Enlightenment suggested urinating through a spouse’s wedding ring. Beginning in the 18th century, electrical belts and beds also promised help.

In the years leading up to the introduction of Viagra, men often had to turn furtively to the back pages of nudie magazines to find “miracle” creams and gels—or supplements like ginseng and (the aptly named) horny goat weed. And if they tried the medical route, intervention might have involved painful injections or silicon rods and pump-activated inflatable cylinders that were surgically implanted in the penis. Ouch.

Undoubtedly, Viagra offered a dramatic improvement on these options. And it’s always a good thing to lessen stigma around sex. Still, despite the liberating effect it had on men, the drug also reinforced several harmful stereotypes about sex and relationships. For many in our instant-gratification culture, the drug was seen as a quick fix not only for an aging appendage, but for fragile psyches and relationships as well. The little blue pill promised eternal youth, sexual prowess and extreme virility, handily regenerating lackluster marriages by making sex last forever.

But the fact is, Viagra just helps increase blood flow to a man’s nether parts; it doesn’t bestow erotic intelligence. Forget connection, pleasure, intimacy, sensuality—with Viagra, the emphasis was on getting it up, getting it in and getting it done. This magic-bullet approach to relationships limits possibilities. The message of Viagra—that a big erection equals great sex—de-emphasized the physical, emotional and erotic communication necessary to true intimacy.

Indeed, in a society where the cultural construct of manhood is linked to impossible standards of constant, on-demand performance—economic, sexual, or otherwise—the possibility of failing to deliver can spell humiliation. Viagra has offered an enticing shield against embarrassment, a promise that penetrative sex—ie. robust manhood—could always be on the table. But here’s the thing: From behind this barrier, a man doesn’t have to reckon with the very feelings of vulnerability that, ironically, might help him grow his empathy and sensitivity, and connect more honestly and intimately with his partner.

And what do intimate partners say? Certainly, men and women alike have welcomed their partner’s renewed ability to get—and keep—it up. On the same-sex side, some men call Viagra a godsend, since erections help condoms stay on, reducing the risk of disease transmission. Some women, though, have expressed mixed feelings about the drug. With its emphasis on facilitating intercourse-based sexual encounters, Viagra has contributed nothing to the understanding of the elusive female orgasm. In fact, with a recent study finding that more than 80% of women don’t climax through intercourse alone, the drug has likely widened the gulf between men’s experience of sexual pleasure and women’s. Meanwhile, some women wondered when drug companies would be offering a “little pink pill” to address their own sexual dysfunction and low libido. And others reported feeling upset that the drug had “disrupted” their sexual routines with their partners—or reintroduced activity they thought they were “done” with. In one “Saturday Night Live” skit from 2000, a series of exasperated women acidly “thanked” Viagra; one furtively poured the pills down the toilet.

About 10 years ago, I attended a panel at a urology conference where speakers were asked: Is it appropriate to prescribe Viagra to men who don’t need it? The debate was vigorous and fascinating to me. I still don’t think there’s one right answer. Viagra itself has been an amazing contribution to the evolution of sexuality—in some ways, it’s as important as contraception for women. But erection is just one aspect of sex, and a little blue pill will never replace communication and eroticism. It alleviates performance anxiety, allowing partners to focus on everything that comes before, during, and after—on what kind of lover they want to be. For the next 20 years of Viagra’s history, it should be celebrated as the beginning of a conversation—not the end.

Psychotherapist Esther Perel is recognized as one of today’s most insightful voices on modern relationships. Fluent in nine languages, she holds a therapy practice in New York City and is a certified sex therapist. The author of bestsellers Mating in Captivity: Unlocking Erotic Intelligence and The State of Affairs: Rethinking Infidelity, Esther also hosts the podcast “Where Should We Begin?” Follow her on Twitter at @EstherPerel.