A popular Chinese author said on Monday many parts of his science fiction trilogy, The Three-Body Problem, have been edited by a US publisher in the English edition for gender discrimination.

Liu Cixin told the Global Times he wrote on popular online forum newsmth.net on Sunday that Tor Books made more than 1,000 edits in The Dark Forest, the second book of the trilogy, some of which touched on gender discrimination. This included a reference to the secretary general of the United Nations as a "beautiful woman" and four males as the most important protagonists.

Words used to describe women, such as "purity" and "angelic," were deleted as well.

Liu said that he personally replied to a post that questioned the credibility of the book's foreign translator, adding that he accepts the need for the edits.

"Of course, there are cultural differences," he said. "I understand these changes."

The English version of the first book of the trilogy was published in 2014. The second and third are in the process of being translated by Joel Martinsen and Ken Liu, respectively.

The cover of The Dark Forest has been released and is expected to be published in the US in August.

Liu's fans accepted the edits with mixed feelings. "The story only presents a world, but how to interpret that world rests with the readers. It's a private process," said Zhu Shiyu, a fan from Jiangsu Province. "The editors don't have the right to force their own interpretation of a piece of work."

Meanwhile, others said that female characters in the book were unfavorably portrayed.

The Shanxi-based science fiction writer was nominated for the Nebula Awards in February and the Hugo Awards in April. He is widely known for his popular trilogy, which features struggles between aliens and humans on Earth against the backdrop of China's Cultural Revolution (1966-76) when a secret military project tried to contact aliens.