(FORTUNE Magazine) – With more women than ever before scaling the corporate heights (FORTUNE does an annual "50 Most Powerful Women in Business" issue, for heaven's sake), you would think--wouldn't you?--that equal pay between men and women doing the same work would be a given. Alas, no. "By a strange coincidence I had just discovered, a day or two before reading your Feb. 18 column, that I (female) am earning about $15,000 a year less than two colleagues (male) who do the same job I do, with virtually identical backgrounds and levels of experience," writes a reader named Michelle in Washington State. "I've scheduled an appointment with my boss to talk about this, but in the meantime, at least I know I'm not the only one." Far from it. The issue was raised by a reader signed A Penny for Your Thoughts asking what to do about a big, apparently gender-based pay shortfall. It struck a nerve with hundreds of you--and many of you weighed in with similar tales. Then in March came a much publicized study by the federal General Accounting Office: Between 1995 and 2000, it seems, in seven of the ten industries that employ the most women, the pay gap between men and women managers actually got wider. In entertainment and recreational services, for instance, female bosses in 2000 earned just 62 cents for every dollar their male colleagues made, down from 83 cents in 1995. Nor do the GAO's findings appear to be a fluke. Consider what the Graduate Management Admissions Council found last year when it surveyed 4,500 MBAs. The women polled had earned 13 cents per dollar less than men before they got their graduate degrees, and 7 cents less afterward.

Much of the gap may arise from women's greater likelihood to take time off to have children. The GAO's research revealed that men's and women's pay tends to be equal until about age 33--the age at which many college-educated, management-track women begin to raise families. Once they have kids, women managers as a group earn about 66% of what their male counterparts make. The study also showed that 60% of women managers didn't have young children at home, either because they had no kids or because they waited until their children were grown before taking on management jobs. For men, the reverse is true--60% of male managers are also dads. The Economic Policy Foundation, a nonprofit research group (www.epf.org), took this analysis one step further and compared the earnings of single, childless women with single men's, and discovered that the unattached females earn slightly more than men, or 101.6% of what the guys make. By these lights, it's only the career interruptions caused by bundles of joy that hold so many women's pay below that of men's in the same jobs.

You can't send the little darlings back (not that you ever wanted to), so what else can women do? "In my years as a hiring manager for a large electronics company, I've noticed time and time again that women hesitate to haggle when it comes to pay," writes a reader signed George. "A man will come to an interview with a certain salary figure in mind and try to negotiate to reach that number. A female candidate is much more likely to accept whatever is being offered, almost as if compensation were not important enough to be worth much discussion. It's possible that some employers discriminate against women and try to lowball them, but I think women themselves have to learn to speak up, and I've taught my three daughters to do so."

A reader named Gloria agrees:

"Your advice to try and get as much information as possible about one's value on the open market was right on. After three years without a raise, I started to suspect that I wouldn't get one until I asked for it. I went in armed with numbers on the going rate for people in my job, in my industry, at my rank, and got an adjustment that put my pay where it belongs. It goes against the grain for many of us, who were raised not to discuss money or (God forbid) make any demands, but if you're willing to look out for your own interests, you can certainly get results."

The only recent topic in this space to generate more mail than the gender gap is that of references, raised by a correspondent in the March 18 issue who had sued his former employer, left the company with a fat out-of-court settlement, and was (somewhat belatedly) worried about what his old bosses would have to say about him. A veteran executive recruiter who asked to remain nameless suggested that anyone with this problem--and there are lots of you, it turns out--might try encouraging a friend to call the old boss for a reference, posing as a prospective employer, just to see. Now, this column is on record as being opposed to all forms of trickery and subterfuge in business on the grounds that anything unethical will ultimately be self-defeating. (I don't have to invoke the E-word, do I?) On the other hand, it might be fun.

In any case, there may be less--and less rigorous--reference-checking going on than one might suppose. Writes a professor at the Haas School of Business at Berkeley: "I teach more than 1,200 students a year, so you can imagine how many times students ask if they may use me as a reference. Fewer than one in 100 prospective employers actually call me--and the ones who do almost never ask the right questions: 'Was he ever late with an assignment? Do you know him to be honest and reliable? How does he respond to criticism?' They ask a general question and get a general answer, and there you are."

E-mail: askannie@fortunemail.com Mail: Ask Annie, FORTUNE, 1271 Avenue of the Americas, Room 1559, New York, N.Y. 10020. Please include an afterwork phone number. Annie offers additional advice at www.askannie.com.