“This makes me sick — as a man I can’t stand this,” one Weibo user said. “Since you want women not to have premarital sex, then please tell all boys to do the same.”

The publisher should “name itself the 18th Century Publishing Group,” another online user said.

In addition to fears about the harm such attitudes inflict on girls, the online reaction reflected concern about the lack of sex education in China. Teenagers often talk about how their parents explained to them as children that they emerged from armpits, or even from trash cans.

Anatomy is commonly taught as a substitute for sex education. In schools with rudimentary sex education, the message for girls is often abstinence, women’s rights campaigners say.

The textbook, first issued to high school seniors in Jiangxi Province in 2004, is old and seems to have had a limited circulation. Apparently embarrassed by the outcry, the publisher, 21st Century Publishing Group, told Sixth Tone the book would be revised.