We've come a long way, baby.

Or have we?

Despite a hefty dollop of enlightenment, women still face constraints in the workplace that men do not. Research, for instance, shows that when women negotiate hard (as they're often urged to do), they actually are penalized for being unlikable. Though toughness often works for men, it can backfire for women.

You can rail against the unfairness of this double standard, but a recent study out of the University of California at Berkeley has another, more retrograde suggestion: Try flirting instead.

The series of studies led by Haas School of Business professor Laura Kay asked pairs of negotiators to rank the effectiveness of their partners, then quizzed female participants about the extent to which they employed social charm. For women--but not for men--being personally warm and charming was associated with greater effectiveness.

Even more worrying was a second experiment involving a fictional car buyer named Sue.

When male car sellers were confronted with "serious Sue," who asked for the seller's best price in a friendly but no-nonsense manner, they were less likely to negotiate and lower the price than when they were treated to the charms of "playful Sue," who, according to a Haas Research News release, "greets the seller by smiling warmly, looking the seller up and down, touching the seller's arm, and saying, "You’re even more charming than over email." That was followed by a playful wink and the female buyer asking, 'What’s your best price?'" (Thankfully, no actual woman was made to do this for the study--the men were simply asked to imagine the two Sues.)   

Though the behavior of "playful Sue" may sound outlandish to some women, there are no shortage of high-powered and deeply serious professional women that admit to using their feminine charms to get what they want, including Clinton-era Secretary of State Madeleine Albright, who has admitted to flirting with male foreign leaders on the job.

If you can stomach the idea of playing to Mad Men-era stereotypes (one can't help but wonder if "playful Sue" took after the likes of office manager Joan and Marilyn Monroe and opted for lipstick and figure-hugging fashions) and plan to follow Albright's lead, keep things subtle--"The key is to flirt with your own natural personality in mind. Be authentic. Have fun. That will translate into confidence, which is a strong predictor of negotiation performance," says Kay. So, no breathy, Happy-Birthday-Mr. President voice, then.  

The study's bottom line seems to be that, sure, there is still plenty of sexism when it comes to women's behavior at the negotiating table, but if you're more interested at any given time in getting a good deal than challenging stereotypes, then flirting may be the way to go.

But perhaps when it comes to the bottom line for most women, it's also worth factoring in whether playing up to entrenched unfairness in this way simply reinforces it. 

Are you comfortable using your feminine charms in negotiations?