We take it as an article of faith that suburban swingers from decades past engaged in a partner-swapping phenomenon known as key parties. As the lore goes, sets of car keys picked from a fishbowl would determine randomized sexual pairings of Quaaluded-up couples who would then supposedly go off and fuck.

But did key parties really ever happen? Or did they grow into a widely accepted urban myth after Hollywood invented them? SF Weekly sifted through 50 years of human sexuality literature to see if we could lock down the truth about the legend behind key parties.

Their many depictions in television and film don’t prove their real-life existence. The best-known cinematic key party is in Ang Lee’s 1997 black comedy of sexual errors, The Ice Storm, although Jim Carrey’s 2000 How the Grinch Stole Christmas reboot also depicts keys in a fishbowl at a highly sexualized holiday gathering of the Whos.

Key parties have turned up in TV plotlines of That ’70s Show, Masters of Sex, and even The Simpsons. (In the 2011 episode “500 Keys,” Marge and Homer attend such a function without knowing what it is. A shirtless Dr. Hibbert then gets fresh with Milhouse’s mom, and Milhouse’s dad is none too pleased.)

The earliest real-life key party reference SF Weekly found was a 1965 lecture on “wife-swapping” by psychotherapist Dr. Albert Ellis. “Whichever car key you get, you get the wife, if you’re the male that goes with this particular set of keys,” Ellis explains. “This is done on a chance, you might say a raffle kind of basis. This is probably the rarest kind of mate-switching today.”

So the concept was out there in 1965, and that suggests people may have tried it.

“Humans are carnal creatures,” Center for Sex and Culture co-founder Dr. Robert Lawrence says. “If you give them an interesting sex idea, they will try it out or talk about it.”

But it may be all talk. The 1970 Journal of Sex Research article “Co-Marital Sex and the Sexual Freedom Movement” labels the phenomenon a myth. “Our data suggest a number of other false myths, but we cannot deal with them all,” co-authors James and Lynn Smith wrote. “There is one, however, that bears mention at this time, and that is the ‘key party’ myth.”

“We were never even able to find an individual who had attended one,” they added in their 1967-68 study of hundreds of Bay Area sexual subculture participants. “Evidently, they do occur, and we have unsubstantiated reports concerning them, but we suspect that the proliferation of the key-party concept has been supported for the most part as a result of fear and fantasy.”

Undoubtedly, the structure of a key party is right out of a straight-male pipe dream. Key party lore is exclusively heterosexual, women are not afforded sexual veto power, and men are guaranteed a partner with no chance of rejection. This all seems out of line with even the earliest sexual liberation ethics.

More notably, we found zero firsthand accounts.

“I have never been to an actual key party, been invited to a key party, or interviewed someone who has personally attended a key party, whether in the 1960s or in the decades that followed,” Katherine Frank wrote in her 2013 group sex cultural anthropology, Plays Well in Groups. “I haven’t found reliable scholarly accounts of key parties, though they are sporadically mentioned.

“Such a lack of evidence screams ‘urban legend,’ ” she concludes.

There are researchers who maintain that key parties definitely happened. Investigative journalist Terry Gould says of his 1999 volume The Lifestyle: A Look at the Erotic Rites of Swingers, “According to two doctors of sexology named Joan and Dwight Dixon, who have been in the lifestyle since the ’60s and writing on sexuality in journals for two decades, the original spouse-sharers were none other than World War II fighter pilots,” Gould has said. “It was the pilots and their wives who invented the term ‘key club,’ which was unknown in the ’40s, [and] became widely known in the ’50s and ’60s.”

That analysis is based on secondhand stories — which determines whether you believe key parties happened. Do you count the retelling of other people’s 1960s oral histories as proof? Then sure, somebody said that somebody said key parties happened.

But a rigorous, fact-based analysis shows little proof, and relegates key party rumors to the level of urban legends like gerbilling, rainbow parties, and “Hot Karls.” You can Google these terms if you must. But we don’t recommend you do so from your workplace computer, or HR might get a little keyed up.