July 11, 2013 -- Joy Chen is a superstar in China, the champion of young women known as "leftovers" -- those who are still single in their mid-20s and scorned by all.

"Their value is derived from their marital status," Chen told ABCNews.com. "Women who are married are normal; those who are unmarried are abnormal."

Chen is the author of "Do Not Marry Before Age 30," a pop culture bestseller that offers dating advice and strives to help women reach their full potential. The book is a latest sensation among a new class of working women in China, some of the best educated in the world.

"There is a deep insecurity among women if they are not married: How are they going to live and survive," said Chen, a Chinese-American who once served as deputy mayor of Los Angeles.

"When you reach 25 and 26, no one wants you anymore," she said of the attitude. "You are no longer beautiful and no longer loved and lose your value as a human being.

"One woman told me she was a leftover at 22," she said. "It's really hard for Americans to imagine that kind of pressure. And it comes from all directions -- from parents, from colleagues at work, everyone you meet in a business capacity and socially."

Her new bilingual eBook, part memoir, part self-help guide, was originally written in English. The Chinese government commissioned and published the book, initially in Chinese, promoting it through the state media to help the women find husbands.

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"It's empowering to let women know they don't have to get married to have a role of importance in society," said Chalsa Loo, a clinical psychologist from Honolulu with an expertise in gender and in ethnic diversity.

"This kind of patriarchal mentality is not exclusive to China," she said. "You look at the different terms in the West. Why is a single woman an 'old maid' and a single man is an 'eligible bachelor'?"

Chen called her book "funny and friendly," a cross between Gloria Steinem and "Sex in the City." Women have been flocking by the thousands to her speaking engagements.

Last year, the All-China Women's Federation named Chen "Woman of the Year."

"It's more of a guide on how to be happy and confident in your own life -- how to love yourself," she said of the book.

But it also includes techniques she learned while working as a global headhunter after her stint in city government.

Chen said she had been dating since she was 18, but didn't marry until she was 38. Now, she gives advice learned from the pitfalls of her own dating years to young career women looking for confidence -- and Mr. Right.

Today, at 43, she is the mother of two children and splits her time between California and China, where she writes a column for the Wall Street Journal and the fashion media.

"This is a strange period in Chinese history," said Chen. "This generation of women is suddenly incredibly well-educated."

She called it a kind of cultural "whiplash."

"They are like a speeding train, getting the best education in the world and, suddenly, they are in the work force and told to put on the brakes and go in the other direction back to women's roles from the 5,000 years of Chinese society," she said. "For women, that is the source of their security and their survival."

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This cultural phenomenon exists in all Asian countries rooted in Confucianism, according to Dudley L. Poston, Jr., professor of sociology at Texas A&M University, who has worked as a demographer in both South Korea and China.

Family members are remembered with ancestor tablets, similar to photos Americans have of their grandparents. But those tablets can only be displayed by sons.

"There was really no way for a woman to be single and to be legitimized," said Poston. "The only way was if they get married and have a son."

Poston said a new class of marriage-age women with professional careers is emerging in China -- the "single nobles" or "danshan quizu" who are rejecting the constraints of the past. They are electing to stay single and delay marriage by 10 to 15 years.

"There has been a relaxation in sexual activity so that young women can engage and it's not as frowned on," he said. "They can travel, so they don't have to be messing around with mothers-in-law, who treat the young bride, some as young as 15 and 16, as a slave. ... They manage their own money."

"This kind of behavior is starting to disturb the male-female marriage-age equilibrium," he said. "The 'single nobles' phenomenon is taking away even more potential brides. This is a big issue these days in China."

As career women wait to marry, and because of the lopsided birth rate favoring males, "a million extra boys are not finding brides, according to Polston.

"We estimate 45 to 55 million boys who, when they are marital age, won't find girls available to marry," Polston said.

A reduction in fertility rates, strong cultural preferences for boys, medical techniques that allow sex selection and the "physical and cultural" ease of abortion contribute to that imbalance.

"The government encouraging women to get married will provide more unbalances," he said.

But Chen said she has seen more women who view themselves as "leftovers" rather than "noble singles."

"In the past year of meeting tens of thousands of women, I only met one of those," she said. "Much more of what I have seen is women who want to be proud of lives filled with accomplishments, but are completely stigmatized."

She said these attitudes encourage women "just to get married."

"They marry the nearest guy and it causes trouble," she said. "There is an exploding divorce rate and, for the first time, China is creating children of divorce."

Chen said the book is "the perfect encapsulation of all that is old and all that is new -- all the contradictions in China today."

"One of the things we keep hearing all over again in pop culture is there are very few role models with success in their career and a happy family life," she said. "My intention is to start the conversation these women need to have amongst themselves."