This month marks the 15th anniversary of a heart drug that accidentally launched a sexual revolution.
Since it was approved for sale in the United States, Viagra has helped more than 25 million men get and keep an erection, according to Pfizer's website.
Thanks to the pharmaceutical giant's famous marketing campaign, erectile dysfunction is no longer a shameful secret, but simply something to "ask your doctor" about.
Whether the "blue diamond" has also helped couples prop up their flagging love lives, however, is up for debate.
In a recent interview with CBC News, London, Ont.-based clinical psychologist Dr. Guy Grenier says Viagra is "tremendously overprescribed" by health professionals who would rather write a prescription than broach a potentially squirmy subject like sexual dysfunction. He suggests people would benefit more from sex education than a sex drug.
"A lot of sexual performance issues have nothing to do with blood flow," Grenier says in the online report. "They have to do with relationships issues, or animosity, or attraction, or communication -- all kinds of things."
OK, well, what if we could take drugs to do those things better?
What if there were a little heart-shaped red pill that could enhance intimacy by bringing back the loving-feeling brain juices that bonded us in the first place?
After all, as evolutionary biologists tell us, the set of biochemical rewards and attachments we know as romantic love is just nature's way of getting us to mate. Two humans form a bond to ensure their offspring are cared for and kept alive. Once the kids are old enough to have kids, natural selection doesn't care whether or not their parents continue to have an emotionally satisfying relationship.
This wasn't really a problem until we started living well beyond our reproductive years. We used to conveniently die before our brains ran out of love juice.
Could this explain the high divorce rate? Could drugs help?
A trio of Oxford ethicists say yes.
In a recent issue of The Atlantic, Brian Earp, Anders Sandberg and Julian Savulescu, who have written extensively on the topic, state the case for chemically enhancing not only our relationships, but our breakups as well.
The high divorce rates and long-term relationship breakup rates in countries where both partners enjoy freedom -- especially economic freedom -- are evidence, they say, that our "evolved pair bonding instincts" are no longer serving us.
"We are simply not built to pull off decades-long relationships in the modern world," Earp and his colleagues told The Atlantic in an email interview. "Nature designed us to be together for a while, but not forever -- and once we push beyond the natural childbearing boundary, we are, in a sense, living on borrowed time."
In the article, the Oxford ethicists argue that using love-enhancing drugs wouldn't be much different than trying to save a relationship with antidepressants or Viagra.
In their research paper titled Neuroenhancement of Love and Marriage: The Chemicals Between Us, they go so far as to say such pharmaceuticals could be a major step toward "biological liberation."
"Imagine that we could retain the attraction to our lifelong partner that we had in the first stages of relationship," the ethicists write. "Or imagine a long-term couple using drugs to stimulate sexual appetite for each other, rekindling intimacy and all the relationship-stabilizing effects of sex. Alternatively, in couples with mismatched sex drives, desire could either be dampened or increased in one partner."
Such emotional engineering is currently beyond the ken of modern science, but there is apparently a growing field of research dedicated to it.
The Atlantic article mentions two potential love drugs: oxytocin, sometimes called the "cuddle hormone" for its role in mother-infant bonding, and MDMA, popularly known as ecstasy.
When researchers at the University of Zurich gave oxytocin nasal sprays to romantic couples during an argument, it facilitated positive communication and reduced stress levels. MDMA, meanwhile, apparently used to be handed out in couple's therapy to "boost empathy and improve communication skills," and Earp says "there has been a recent resurgence of scientific interest in possible therapeutic uses" for it.
Closer to home, University of Manitoba ethicist Arthur Schafer says creating so-called love drugs is "utter folly," if not "wicked folly."
During a campus debate, he said looking to pharmaceuticals for a quick fix to a complex problem like human relationships is symptomatic of a "medicalizing society" that believes there should be a pill for every ill.
"We're living at a time when brain chemistry is being touted as the key to what's wrong in our society," said Schafer, director of the U of M's Centre for Professional and Applied Ethics. "I just don't buy it."
Drug companies' desperate but failed attempts to develop a female version of Viagra just go to show that desire and intimacy involve more than biochemistry, he says. Never mind how "inauthentic" chemically enhanced relating might be.
It's not just intimacy itself that matters, Schafer said, but also the means with which we achieve it. For example, spending time with a partner, showing gratitude, and making loving gestures can all raise "love hormone" levels naturally.
Arguing the other side, U of M philosophy professor Neil McArthur said we should welcome the development of love drugs and add them to our therapeutic arsenal of tools to mitigate the inevitable misery caused by the mismatch between our romantic ideals and our biological reality.
In a sense, they're no different from other drugs that were created to ease pain and discomfort.
"If we see someone suffering and there's a drug available, we'll give it to them," says McArthur, whose research focuses on the philosophy of sex and love, which he blogs about at morallust.com.
Love drugs could be used in "controlled and limited ways," he says, to connect couples and to achieve the kind of relational breakthroughs that therapists typically make.
But U of M psychology professor Marian Morry, whose research focuses on interpersonal relationships -- between friends, dating partners and spouses -- says the real issue we need to address is our idealized image of love and marriage.
We're conditioned to expect high levels of passion, intimacy and commitment in our marriages throughout our lives, Morry says, where research shows that in most relationships, passion wanes over time, she says. Happy long-term marriages are typically those with high levels of communication and commitment, where the partners see themselves as best friends.
There's no "magic bullet," says Morry, who conducts her research in the U of M's Close Relationship Laboratory.
"Perhaps we should stop buying into Hollywood images of romantic relationships and instead focus on the work that is required."