BOSTON -- First, let me clear up one small fact: Matthias Mehl is married. This will come as shock to some of the men who e-mailed the psychologist after reading his research showing that men and women are equally talkative.

These men dismissed his work with a wave of the ring-bearing hand. "Clearly, you aren't married," they wrote. "I'm married, and let me tell you that women do talk more."

Pity poor Mr. Mehl. By disproving the notion that women were the Chatty Cathys of the species, the University of Arizona researcher had thrown science up against stereotypes.

This whole story began as an attempt to put a number on the chat gap between men and women. One pop psychologist after another claimed a gap of immense proportions. They said that women used 20,000 words per day to men's 7,000. Or 7,000 words a day to men's 2,000.

But Mr. Mehl decided to count. For the first time, some 400 college students were equipped with recording devices. It turned out, both men and women use about 16,000 words a day. By contrast, the range among individuals was huge. The Chattiest Carl used 47,000 words and the Silentest Sam used 700.

Mr. Mehl may have been the first who counted, but he was by no means the first to challenge the chat gap. A survey of 70 prior studies of men, women and chatter is about to be published by University of California, Santa Cruz psychologist Campbell Leaper. This survey also shows no consistent gap in talkativeness.

Now, let's acknowledge that there is a difference between the quantity and quality of words. Linguistics professor Deborah Tannen has long written about men's "report-talk" and women's "rapport-talk." Mr. Leaper notes that in some of the studies he reviewed, men were more likely to talk among strangers than were women, and mothers more likely to talk with their children than were fathers. If the subject was impersonal or problem-solving, men took up more of the airwaves. If it was personal, women did. But in every situation, our similarities are far greater than the differences.

Researchers have been debunking the notion that men and women are the extremely opposite sexes since Helen Thompson Woolley first reviewed the gender research. That was in 1914. Almost a century later, men's and women's lives are more alike than ever before. But we seem to have embraced old stereotypes as the new, new thing. The tale is in the book titles: Why Men Don't Listen and Women Can't Read Maps. Men Are Clams, Women are Crowbars. Why Men Don't Iron. And, of course, Sperm Are From Men, Eggs Are From Women.

The chat gap is particularly tenacious because it's what University of Pennsylvania phoneticist Mark Liberman calls "an equal-opportunity prejudice." On the one hand, he says, "There are people with negative attitudes toward women who see it as showing women are empty-headed chatterboxes and men are serious." But, he adds, "There's another group who sees women as socially oriented, verbally adept makers of connections and men as tool-oriented, cold-hearted, unconnected loners."

Whichever you pick, the equal-opportunity prejudice is a bulwark against change. In public life, it's easy to tag any woman who speaks up as speaking too much. In private life, wives are supposed to accept the taciturn as masculine.

So here we go, once more into this breach, bearing numbers. They support the much-less-marketable truth about men and women that psychologist Janet Hyde whimsically describes this way: "Men are from North Dakota and women are from South Dakota."

I have no idea how long the math will trump the myth. But for now, Mr. Mehl has given us something to talk about. At around 16,000 words per day per man ... and per woman. Now, is anybody out there studying how much we listen?

Ellen Goodman is a columnist for The Boston Globe. Her column appears Fridays in The Sun. Her e-mail is ellengoodman@globe.com.