Which of the battling groups is right: The activists who say that women are treated unfairly by the insurance industry, or the insurers who say that, if anything, women are getting a special break?

And whose recommendations should a thoughtful person back: Those of activist women, who say both sexes should be charged the same for life, health and auto insurance, as well as individual annuities? Or the insurers, who say that by setting prices according to sex, each sex gets a better break?

Right now, Massachusetts is grappling with this question, and may pass a unisex rule within a couple of weeks. Lawsuits to compel equal rates on individual policies have been brought in Pennsylvania, California, New York and the District by lawyers for the National Organization for Women. So far, their win record is poor. Courts in New York and the District have tossed them out.

In theory, it ought to be easy to resolve the conflicting claims. Just take as a scientific laboratory the state of Montana. Since October, 1985, Montana has required insurers to charge men and women the same price for the same type of coverage. That should provide a clear demonstration of which system works best, right?

Wrong. But first, a little background.

In general, women pay less then men do for life insurance because women live longer on average, hence there are fewer claims in any year. Single women under 25 pay much less for auto insurance, because they have fewer accidents than young men.

On the other hand, women pay more for health and disability coverage, because insurers say women are sick more often than men. And older women get smaller incomes from their individual annuities because a given sum of money might have to be stretched out over many more years. (Pension annuities, however, are paid on a unisex basis.)

A true unisex-pricing system averages the insurance-claims experience of women and men. Under it, women would pay more for their life insurance then they do today while men would pay less. Young single women would pay considerably more for auto insurance while young single men would get a sizable price cut (for marrieds and for older men and women, most auto rates are already equal).

But women would pay substantially less for their individual health and disability insurance, while men would pay more. Older women would get larger monthly payments from their private annuities, while men would get a little less.

That, at least is the theory. What is the fact? To answer that question, the Montana insurance department recently surveyed prices charged by 44 insurers before and after the unisex revolution. The result? Confusion. When you add up all the types of coverage people buy, polemicists still lack proof that women (or men) do better (or worse) under unisex (or single sex) pricing.

To begin with, many insurers raised rates for reasons that had nothing to do with the unisex law. For example, auto-insurance rates rose sharply at many companies for both women and men because of increases in claims. In the second place, many insurers have not truly instituted an average unisex rate, especially the life insurers. Instead, they kept men's rates the same and raised women's rates to the men's level. Compared with what they would pay on a unisex table, both men and women are now being overcharged.

"Women's insurance rates didn't jump a lot across the board," said Dave Drynan of Montana's insurance department. "What happened was that a few companies didn't want to do business in the state so they increased their rates and brought women's rates up, too."

Burton Jay, executive vice president of United of Omaha, says it simply doesn't pay to create a new unisex table for a single state to sell term and whole-life insurance. However, United of Omaha does have a unisex table for one type of policy, universal life, "which is being heavily sold in Montana."

Health insurers, on the other hand, pretty much followed unisex theory. Men's rates consistently rose and women's rates consistently declined (except at Blue Shield, which already had unisex rates).

For young single drivers, women's rates rose at all the companies -- and so did some rates for young men. But part of that increase was due to higher claims. "We averaged the rates between the men and women," says Judith Mintel, counsel at State Farm Mutual.

Over the next year or two, Drynan says, Montana will be asking insurers for the actuarial basis of their insurance rates, to see if they can justify their prices. Maybe then, we'll see what true unisex looks like.endqua