The unnamed engineer asserted in the 3,000-word document that circulated inside the company last week that "Google’s left bias has created a politically correct monoculture" which prevented honest discussion of the issue.
"Distribution of preferences and abilities of men and women differ 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," he wrote.
The memo stoked the heated debate over treatment of women in the male-dominated Silicon Valley that has boiled for months following sexual harassment scandals at Uber Technologies Inc and several venture capital firms.
Google's recently hired vice president of diversity, integrity and governance, Danielle Brown, sent a memo in response to the furore, saying the engineer's essay "advanced incorrect assumptions about gender."
"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," Brown wrote.
"But that discourse needs to work alongside the principles of equal employment found in our Code of Conduct, policies, and anti-discrimination laws," she added.
Google engineering vice president Aristotle Balogh also wrote an internal post criticizing the employee's memo, saying "stereotyping and harmful assumptions" could not be allowed to play any part in the company's culture.
A Google spokesperson told Reuters that the statements from Brown and Balogh were official responses from Google.
The controversy erupted as the Department of Justice continues to press an investigation of alleged gender-based pay discrimination at Google, a unit of Alphabet Inc.. The company has denied the charges.
The episode also sparked debate on the proper limits of free speech in corporate environments.
Entrepreneur Elissa Shevinsky wrote on blogging website Medium that speech "questioning the technical qualifications of people based on race or gender" could fall under Title VII of the Civil Rights Act, which prohibits employment discrimination based on race, colour, religion, sex and national origin.
"Google is not a space where employees should be able to express and share whatever feelings they may have, regardless of how it affects others," Shevinsky wrote.
Former Google privacy engineer Yonatan Zunger wrote on Medium that the unnamed engineer "does not appear to understand the consequences of what he wrote, either for others or himself," and said if the engineer reported to him he'd be fired.
There were also expressions of support for the anonymous engineer. He said in a comment on his original posting that he had received "many personal messages from fellow Googlers expressing their gratitude for bringing up these very important issues," according to a copy of the memo posted by technology news site Gizmodo.
Motherboard, the online news outlet that first reported the employee's memo, reported Sunday that many messages on the anonymous corporate messaging app Blind showed backing for the view that Google's culture was too politically correct.
(Reporting by Sam Forgione; Editing by Jonathan Weber and Mary Milliken)
By Sam Forgione