She has been around since 1921 but looks no older than her mid-30s. She is a model of domesticity, yet no one is sure if she has ever married. She is as conservative as they come, but has just had her fifth facelift. And though studies show she is known to 90 percent of America's housewives, the lady has never really existed.

She is Betty Crocker, a symbol for General Mills, the huge food company, and when her sixth incarnation was recently unveiled it made headlines. The reason is simply that she has become one of the most successful corporate trademarks of all time. Her name is on more than 130 General Mills products from cake mix to instant potatoes, sales of which amount to more than $500 million a year. Since 1950 45 million Betty Crocker cookbooks have also been sold; the newly published Betty Crocker's International Cookbook is already a best-seller.

Betty Crocker began as a pen name for answering housewives' requests for recipes. Samuel C. Gale, an employee of the flour-milling company that was the forerunner of General Mills, reasoned that women would rather hear from another woman. Betty was selected because it sounded friendly, while the surname was chosen to honor William Crocker, a company director who had just retired. Starting in the 1920s Betty had her own radio show, but it was not until 1936 that she got a face—the first of six. Her portraits are always painted (no real person has ever sat as a model), and she is never seen from the waist down.

The woman at General Mills who is most often confused with Crocker is Mercedes Bates. As director of the Betty Crocker Food and Nutrition Center in the Minneapolis suburb of Golden Valley, Bates, 60ish, has shepherded Betty through the trauma of the last four facelifts.

It hasn't been easy. "You don't have to look like a missionary to cook well," one woman complained in 1964. Soon after, prim Betty No. 2 was replaced. A more serious challenge was launched eight years ago when the National Organization for Women filed a class action suit charging General Mills with sex discrimination for perpetuating the image of Crocker as a homemaker. The suit was thrown out of court, but the company got the message. For the 1980 model Bates softened Betty's skin tone, replaced her unstylish flip with a slightly streaked bob and fastened a gold chain around her neck. "I see her as a career woman," says Bates of Elizabeth VI. "A professional first and last."

That, of course, describes Bates herself. She was born in Portland, Oreg. and graduated from Oregon State with a home economics degree the year of Betty's first portrait. By 1948, with a $1,000 loan from her father, a civil engineer, Bates set herself up as a freelance food consultant in Los Angeles. In 1960 Bates moved to New York, where she spent four years as food editor of McCall's before joining General Mills. She became its first female vice-president in 1966.

Crocker's history intrigues Bates, who discovered that back when Betty had her own radio show, a listener fell in love with her voice and sent in a proposal of marriage. He was gently rebuffed. It is Crocker's staying power that is most fascinating. "Today," Bates believes, "it would be impossible to create Betty Crocker. Consumers are just too sophisticated."