Taxi-hailing app Uber has promised an "urgent investigation" into claims of workplace sexual harassment, after a female engineer said misogyny was rife at the firm and women were quitting in droves.
Susan Fowler, a software engineer, wrote a blog post about a "very, very strange year at Uber".
In it, she says her manager tried to have sex with her on her first official day at work, sending her messages about his open relationship.
It's just the latest blow for a company that has gained a reputation as a bastion of Silicon Valley's macho "bro" culture.
But is Uber really any more sexist than other tech giants in the Valley?
Ms Fowler's claims have resonated with many women in the tech world, and surveys suggest her experiences are not uncommon.
According to a 2016 survey, 60% of women working in Silicon Valley experience unwanted sexual advances.
The "Elephant in the Valley" survey found that 87% of the 220 women interviewed had witnessed demeaning comments from their colleagues.
Almost 40% of those who said they were harassed at work did not report the situation, fearing it would damage their careers.
"I was propositioned by a hiring manager early in my career when I was a job candidate," one contributor to the study wrote.
"He clearly indicated that if I slept with him, he would make sure I was promoted as his 'second in command' as he moved up the ladder in the company."
Another said she had turned down her CEO's sexual advances the first time they travelled together for work.
"After that, I was never asked to travel with him again," she said. "This impacted my ability to do my job."
On Twitter, Ms Pao said Ms Fowler's blog post shows "the state of tech in one woman's story, also the story of many women, many people at many companies".
Discrimination is difficult to quantify - especially when victims are unwilling to speak out.
Comparing results from different studies with different questions can be problematic - but there are some hints that Silicon Valley has a problem.
Statistics on sexual harassment vary widely, but an extensive 1992 US national study found that 41% of women had experienced it; and about 40-50% of women in the EU, according to the United Nations.
The 2016 Women in the Workplace study - a major US national survey - found that 19% of the technology sector's top executives are women - broadly in line with sectors like banking, media, or professional services.
The same study found that, across all industries, 30% of women who negotiated for a promotion or a better salary were told they were "bossy" "aggressive" or "intimidating".
In the Elephant in the Valley survey, that rocketed to 84% of women being told they were aggressive (though that question was not specifically about negotiation).
The world's biggest tech companies know they're dominated by white men, and many are funding schemes to address that.
In its annual diversity and inclusion report, Apple said it had closed pay gaps over the past year by analysing salaries, bonuses and stock grants.
Facebook has pledged to give $15m (£12m) to Code.org, a non-profit group teaching young women and underrepresented minorities how to write computer code.
And in 2015, Google told USA Today it would invest $150m (£120m) in workforce diversity initiatives that year, up from $115m in 2014.
At the moment, 23% of Apple's tech employees are women. At Google, it's 19%. And at Facebook, just 17%.
Change comes slowly in companies of this size, so the path could be a long one.
But by broadening the pool of people qualified to work there, Silicon Valley is hoping to change the status quo.