Female engineers who work at Facebook may face gender bias that prevents their code from being accepted at the same rate as male counterparts, according to internal company studies disclosed today by The Wall Street Journal. For Facebook, these revelations call into question the company’s ongoing diversity efforts and its goal to build overarching online systems for people around the globe. The company’s workforce is just 33 percent female, with women holding just 17 percent of technical roles and 27 percent of leadership positions.

The findings come in two parts. An initial study by a former employee found that code written by female engineers was less likely to make it through Facebook’s internal peer review system. This seemed to suggest that a female engineer’s work was more heavily scrutinized.

Facebook claims the issue is with rank, not gender

Facebook, alarmed by this data, commissioned a second study by Jay Parikh, its head of infrastructure, to investigate any potential issues. Parikh’s findings suggested that the code rejections were due to engineering rank, not gender. However, Facebook employees now speculate that Parikh’s findings mean female engineers might not be rising in the ranks as fast as male counterparts who joined the company at the same time, or perhaps that female engineers are leaving the company more often before being promoted. Either possibility could result in the 35 percent higher code rejection rate for female engineers. (Facebook has eight engineering levels that determine hierarchy.)

When contacted by The Wall Street Journal, Facebook called the initial study “incomplete and inaccurate” and based on “incomplete data,” but did not shy away from confirming Parikh’s separate findings. That implies that, at the very least, one of the two situations is true: female employees have a harder time contributing to Facebook’s code base due to scrutiny from male colleagues, or that those employees are not obtaining higher ranking engineering roles that would allow for more code commits due to any number of factors. Facebook points to the lack of female engineers as an industry-wide issue that needs solving, and not something the company can remedy solely on its own.

Facebook’s new mission is to build a global community for everyone

Without access to the studies, we’re unable to verify the methodology or scrutinize the findings for further data points. However, the results suggest potential bias at Facebook most likely shared by most other major tech companies — a vast majority of which are predominantly male.

For Facebook, it’s troubling given CEO Mark Zuckerberg’s grand vision to construct the “social infrastructure” of a new global community, laid out clearly in a new manifesto he published in February. If only male programmers are helping shape the digital fabric of this online world, it runs the risk of excluding viewpoints and considerations important to half the human populace.

When questioned about the findings during a workplace Q&A session last week, Zuckerberg reportedly said gender bias was an “issue,” according to The Wall Street Journal. In a statement given to The Verge, Facebook stands by its analysis of the original study and defended Parikh’s findings:

As we have explained, The Wall Street Journal is relying on analysis that is incomplete and inaccurate — performed by a former Facebook engineer with an incomplete data set. Any meaningful discrepancy based on the complete data is clearly attributable not to gender but to seniority of the employee. In fact, the discrepancy simply reaffirms a challenge we have previously highlighted — the current representation of senior female engineers both at Facebook and across the industry is nowhere near where it needs to be.

Update 1:10PM ET, 5/2: Added statement from Facebook.