Talk about a hot-button issue: Despite women’s social and economic gains over the last 35 years, more American women report being less happy.

In fact, a new gender gap has emerged: Men are now happier than women.

That’s according to a study, The Paradox of Declining Female Happiness, by two University of Pennsylvania economists to be published in the American Economic Journal in August.

But the word’s out, igniting gender battles online as both sides point fingers. “Typical complaining women,” and “raving, loony feminists,” snipe some males. “We have too much to do,” and “sexist jerks,” females retort.

Happiness, it turns out, is far more nuanced than that and varies by nationality. A Canadian expert says women here not only still top men in life satisfaction, but also score higher on the happiness scale — which includes issues of social security — than their sisters to the south. Who knew?

It’s too early to tell if the American findings are a harbinger of a new gender gap here, of women’s waning well-being.

“Is it indicative of social trends that will catch on and spread, or is it just a feature of U.S. life?” economist John Helliwell of the Canadian Institute for Advanced Research asks rhetorically. One potential sign: Canadian teenage girls are reporting less life satisfaction than the boys.

Betsey Stevenson, co-author of the Paradox study, has no easy answers. This pursuit of happiness business is serious stuff. Economists use such life satisfaction findings to help evaluate public policies, explains the assistant professor at the University of Pennsylvania’s Wharton School.

She and co-author Justin Wolfers analyzed three different U.S. surveys going back to the 1970s. In all three, women’s delight in life diminished more than men’s. That held true for women of all ages, education levels, married or single, working or not, mothers or childless.

The two economists looked further for clues. Gauges of marital happiness showed men and women declining equally. “That’s just sad,” comments Stevenson.

• Canadian women top men in life satisfaction, says expert