We've all heard about how guys are supposedly more likely to cheat because they're wired to sow their oats. Turns out that the original study that came up with this claim might have been flawed all along.

The initial claim is based on an infamous fruit fly study conducted 60 years ago by English geneticist Angus John Bateman.  But researchers at UCLA reexamined these findings, saying that the long-accepted theory that men are hard-wired to be unfaithful while women seek monogamy is totally flawed.

Bateman's method involved isolating three fruit flies in a jar, and examining the results of their procreation and the parentage of the offspring spawned. Since DNA analysis was not available at that time, Bateman had to rely on severe mutation as proof of lineage. By looking only at the offspring with two mutations, he could know accurately which fruit flies had mated to produce them.  He eventually determined that males produced many more offspring from multiple mates while females produced the same number of adult children whether with one mate or many. This conclusion was what shaped the way we have understood sexual promiscuity and infidelity ever since.

But according to Dr Gowaty, this process had a singular but 'fatal flaw'. She explains why to Science Daily:
In their repetition -- and possibly in Bateman's original study -- the data failed to match a fundamental assumption of genetic parentage assignments. Specifically, the markers used to identify individual subjects were influencing the parameters being measured (the number of mates and the number of offspring). When offspring die from inherited marker mutations, the results become biased, indicating that the method is unable to reliably address the relationship between the number of mates and the number of offspring, said Gowaty. Nonetheless, Bateman's figures are featured in numerous biology textbooks, and the paper has been cited in nearly 2,000 other scientific studies.
"Our team repeated Bateman's experiment and found that what some accepted as bedrock may actually be quicksand. It is possible that Bateman's paper should never have been published." she says. As for why the stereotype still persists, Gowaty believes that it was probably a way for society to tolerate these cheaters among us:
"...Bateman's result was so comforting that it wasn't worth challenging. I think people just accepted it."
Hmm, makes you wonder what other kind of myth stereotypes are out there just waiting to be busted by science.