Women are not advancing in the workplace at the same rate as men, but it's not for the reasons that often get cited -- i.e. a desire to start a family and achieve a better work-life balance.

Rather, women face more barriers to advancement in the workplace, stemming from unconscious biases, inauthentic commitments to gender diversity and less advancement in "line" roles, according to a new study from McKinsey & Co. and LeanIn.Org.

The consulting firm and Facebook COO Sheryl Sandberg's organization for advancing woman surveyed 118 companies and 30,000 employees, including 13 media and telecom companies, about the state of women in corporate America.

The study came to the discouraging conclusion that it might take another 25 years to reach gender parity at the senior VP level and more than 100 years in the C-suite. It was valuable, however, for dispelling theories that the lack of women in tech at all levels is attributable to the choices they themselves make. (See A Vast Valley: Tech's Inexcusable Gender Gap.)

One the study's chief findings is that women are not leaving their companies at higher levels than men. In fact, their exit rate is lower at every level from entry to C-Suite, except for senior managers and directors, for which women tend to leave slightly higher than men. At the SVP level, women are 20% less likely to leave than men, and at the C-level it jumps to 50%. (See More Women in Tech Is Critically Important.)

So why aren't women being promoted at the same rate as men (which the study finds is true as women are increasingly less represented as titles advance)? McKinsey and Lean In suggest it's because fewer women hold roles that lead to the C-suite. A majority of women initially hold line roles, defined as positions with profit-and-loss responsibility and a focus on core operations, but by the VP level, more than half hold staff roles, or support positions like legal, human resources and IT. The majority of men, meanwhile, hold line positions at every level.

Line roles traditionally led more directly to the C-suite, but women who hold line roles have lower odds of reaching the top than those in staff roles, McKinsey says.

Interestingly, women at all levels of a company believe they are given fewer opportunities to advance because of their gender and believe they are disadvantaged by their gender. They report being consulted less on important decisions and are three times more likely than men to say they missed out on an assignment, promotion or raise based on their gender. Seventy-two percent of men thought women and men had the same opportunity, but two thirds of both thought there was room for improvement.

"Two-thirds of both women and men do not think their companies are meritocratic, suggesting a broad appetite for cultural change," the study reads. (See Championing Change: It's a Cultural Thing and What Is Your Company's Gender IQ?)

Light Reading is hosting its next Women in Comms breakfast in London on November 5, ahead of the OSS in the Era of SDN and NFV: Evolution vs. Revolution show. Please join us for the free and fantastic morning by registering here.

Despite the clear desire for cultural change, and though many companies have adopted diversity programs, it's not clear that corporate executives are fully committed to fulfilling diversity goals. While 74% of companies reported that gender diversity is a top CEO priority, less than half of workers believe it, and only one-third see gender diversity as a top priority of their direct manager.

Women felt the disconnect even more than men -- while 70% of men think gender diversity is important, only 12% believe women have fewer opportunities. Thirteen percent even said that it was harder for them to advance because they felt disadvantaged by gender-diversity programs.

McKinsey and LeanIn.Org put forth a number of recommendations for how companies can tackle what is clearly a huge, multi-faceted problem with a number of disconnects. They suggest:

"While there is still significant work to do, it is encouraging to note that a majority of women and men report being satisfied with their careers, family situations and personal lives," the report concludes. "Building on this foundation, corporate America can eliminate the barriers women face and help all employees achieve their full potential."

— Sarah Thomas, , Editorial Operations Director, Light Reading