Michael Kovac/Getty Images for Vanity Fair Andreessen Horowitz cofounder Marc Andreessen
During an interview with Fortune's Dan Primack, Andreessen said that the firm's first GP offer (after him and cofounder Ben Horowitz) went out to a female partner - but she's rejected it five times already.
"It's been driving my crazy," Andreessen said.
Andreessen Horowitz has much better female representation than other Silicon Valley tech companies, as more than 52% of its 107 employees are women. But none of the seven general partners, the firm's top positions, are female.
Andreessen wouldn't name the female executive who's turned him down five times. But he said that he's also offered the position to a number of other women, who all happened to reject him as well.
The reason for this, according to Andreessen, is quite simple: demand for female executives are high and the supply of women who work in tech is low.
"I think this is true in other firms, and I think this is true at the CEO level as well, is when you talk to female CEOs, they get so many offers," he said.
"Because there are so few and the need is so intense, they get so many offers, that they're just drowning in opportunity, which is why we think so much of the work has to be at the pipeline and access level, which is we have to get more people developed."
In order to solve this problem, Andreessen said his firm has been doing a lot of grassroots work to improve female and minority employment in tech. It's partnered with outside organizations like Code 20/40 for minority entrepreneurs and Girls Who Code, while it's working with Google board member and VMware cofounder Diane Greene to further spread the word.
"We have to get more people rising up the ranks. We have to get more [female] executives," Andreessen said.
Disclosure: Marc Andreessen is an investor in Business Insider.