Only 3 of the 50 most-loved CEOs in America are women - and the reason why transcends the corner office

Congratulations are in order for Enterprise Holding's Pamela Nicholson, In-N-Out Burger's Lynsi Snyder, and Deloitte's Cathy Engelbert - these three CEOs were the only women to break into the boys club that is the 50 most popular CEOs list.

Glassdoor's annual Highest-Rated CEOs report relies on the input of employees who were asked to rate their CEO and say whether they approve of the way he or she is leading the company.

At first glance, we can see one major factor at play for why so few female CEOs are beloved by their employees: There are simply fewer female CEOs of large companies than there are male. And that's a whole other issue that we address here.

It's understandable why some women CEOs did not make the list. With all that's been happening at Yahoo over the past few years, it's not that surprising its CEO, Marissa Mayor, is taking the brunt with a 70% approval rating on Glassdoor.

But dig a little deeper, and there may be something else lurking just below the surface.

Time and time again, successful women are viewed as less likable than their male counterparts.

According to research by McKinsey & Co. and Lean In, which surveys 132 companies employing more than 4.6 million people, women negotiate for promotions and raises more often than men do, but they're far less likely to receive them. The issue is that, when women negotiate, people like them less for it.

According to the study, women who negotiate are 30% more likely than men who negotiate to receive feedback that they are "intimidating," "too aggressive," or "bossy" - and they are 67% more likely than women who don't negotiate at all to receive the same negative feedback.

"The reason for this pushback lies in many of the unconscious assumptions we all hold about women and men," Sheryl Sandberg, the chief operating officer of Facebook and the founder of Lean In, writes for The Wall Street Journal. She continues:

"We expect men to be assertive, look out for themselves, and lobby for more - so there's little downside when they do it. But women must be communal and collaborative, nurturing and giving, focused on the team and not themselves, lest they be viewed as self-absorbed. So when a woman advocates for herself, people often see her unfavorably."

Every day women make a tradeoff between sounding smart, confident, and assertive and appearing warm and likable.

Sandberg and her team of researchers aren't the only ones to observe this trend.

According to research conducted by NYU psychology professor Madeline Heilman, women's career advancements are often impeded by two kinds of gender stereotypes:

• Descriptive stereotypes attribute certain characteristics to women, like "caring," "warm," "modest," and "emotional." This creates problems, Heilman says, when there's a disconnect between what women are perceived to be like and what attributes are necessary to successfully perform in male gender-typed roles.
• Prescriptive gender stereotypes designate what women and men should be like. With this kind of stereotyping, women are disapproved of and punished socially when they directly or seemingly violate the prescribed ways they should act.

Numerous studies have shown the disturbing role prescriptive gender stereotypes play in the workplace.

Another study conducted by Heilman showed that successful women working in "male domains" are penalized when they are perceived to be less nurturing or sensitive, since they violate gender-stereotypical prescriptions.

Women who violate prescriptions of modesty by promoting themselves at work were found to be less hirable in a Rutgers University study - and a study conducted by Harvard's Hannah Riley Bowles showed women were penalized by evaluators more often than men for initiating negotiations, thus violating the prescription that women be passive.

After analyzing more than 248 performance reviews, Kieran Snyder wrote in Fortune, "negative personality criticism - watch your tone! step back! stop being so judgmental! - shows up twice in the 83 critical reviews received by men. It shows up in 71 of the 94 critical reviews received by women."

Women's reviews included statements like, "You can come across as abrasive sometimes. I know you don't mean to, but you need to pay attention to your tone," and, "You would have had an easier time if you had been less judgmental about R-'s contributions from the beginning."

Of course, this isn't to say that things are hopeless, and to play the game, women need to just sit down and shut up. Quite the contrary. The McKinsey and LeanIn study also found that women who lobby for a promotion are 54% more likely to report getting it than women who don't.

And Deloitte's Engelbert, who became the first woman CEO of a big four audit, accounting, and consulting firm in 2015, told Wharton School that she credits her confidence and capabilities with rising to the top. "I do believe in 'the cream always rises to the top' Engelbert said. "At least for me it worked."

"We can all think we're discriminated against, and I'm sure many of us are,' Engelbert said. "But I see a ton of optimism in corporate America around the advancement and retention of women."