NEW YORK • Google has found itself at the centre of controversy after an employee in a leaked internal document claimed "biological causes" explained the lack of women in tech leadership roles.

The screed - dubbed "sexist" by the US media - went viral, reviving the simmering debate over a culture of sexism and lack of diversity in tech sectors.

"I'm simply stating that the distribution of preferences and abilities of men and women differs in part due to biological causes and that these differences may explain why we don't see equal representation of women in tech and leadership," read the 3,000-word memo by an anonymous male software engineer.

According to the author, natural aptitudes of men allow them to become better computer programmers. Women, he said, have more "openness directed towards feelings and aesthetics rather than ideas" - meaning they "prefer jobs in social or artistic areas".

In response to the leaked memo, Ms Danielle Brown, Google's new vice-president of diversity, told employees in an e-mail that "it's not a viewpoint that I or this company endorses, promotes or encourages".

"We are unequivocal in our belief that diversity and inclusion are critical to our success as a company.

"Changing a culture is hard, and it's often uncomfortable," she said.

Ms Brown added, however, that "part of building an open, inclusive environment means fostering a culture in which those with alternative views, including different political views, feel safe sharing their opinions".

It was unclear whether the memo's author would face disciplinary action.

Mr Ari Balogh, a Google engineering executive, said in an internal memo that "questioning our assumptions and sharing different perspectives is an important part of our culture".

"One of the aspects of the post that troubled me deeply was the bias inherent in suggesting that most women, or men, feel or act a certain way. That is stereotyping, and it is harmful."

Currently some 69 per cent of Google's employees are men, according to the company's latest figures, a proportion that rises to 80 per cent when it comes to technology jobs.

At Facebook, just 27 per cent of senior executives last year were women.

At Apple, around 30 per cent of total employees are women.

The controversy comes as increasing numbers of women are going public claiming gender-based discrimination in Silicon Valley.

Uber's embattled chief executive Travis Kalanick resigned earlier this year under pressure from investors seeking to clean up the company's allegedly toxic corporate culture.

AGENCE FRANCE-PRESSE