To see why some women make less than some men, look no further than the Geller Law Group, described in a front page New York Times Sunday Business section article by reporter Noam Scheiber.

The women-owned Geller Law Group, based in Fairfax, Virginia, is a small family-friendly law firm that allows women time to be with their children. The firm’s credo: women should not be judged by “face time” in the office.

Partners Maria Simon and Rebecca Geller “have a near-evangelical determination to show that parents can nurture their professional ambitions while being fully present in their children’s lives,” writes Scheiber. The article is accompanied by photos of Ms. Simon dropping off her four-year old son at school, and Ms. Geller helping her four-year old with a toy swimming pool while sending emails to clients.

Simon and Geller are fortunate to have flexible jobs as law partners where they can give parenting the time they believe it deserves. Partners bill themselves out at $280 an hour, less than at leading law firms, and allow time for kids’ activities. Ms. Simon stated that her pay is about half the $250,000 to $300,000 she would have earned at major law firm, but “the freedom she purchased has come at a relative bargain.”

Feminists complain that women are victims of discrimination who earn 78 cents on a man’s dollar. This misleading figure compares earnings of full-time working women to those of men, irrespective of type of job or time in the workforce. But the story of the Geller Law Group shows that women’s choices can result in lower pay. Ms. Simon states that she is glad to be earning 50 cents on a man’s dollar, because this enables her to spend more time with her family.

The same choices can be observed every day in women’s search for flexible jobs. Yale Law School Women just released their 2015 list of the Top Ten Family Friendly Firms. These firms, including Arnold & Porter, Hunton & Williams, and Kirkland & Ellis, are judged on the basis of their willingness to offer part-time and flex-time working hours; family leave; gender equity; and parental leave. Some of the smartest young women in the country are looking for family friendly jobs before they even have children, and these family-friendly jobs tend to pay less.

Becoming a partner in a major law firm takes hours of work, not all of it family-friendly. Yale Law School Women found improvements in parental accommodation, but concluded that usage of these benefits has not increased. The percentage of female partners is 19 percent, the same as in 2008.

The causes of the average wage gap are not hard to find. When in college, women tend to major in the humanities rather than in math, engineering and science. Once they graduate, more women than men work for non-profits, which pay less. Twenty-four percent of women work part-time, and full-time women work on average fewer hours than do full-time men.

When women are compared to men in the same jobs, with the same experience and job tenure, the wage gap practically disappears, according to academics such as Professors June and David O’Neill of Baruch College, coauthors of The Declining Importance of Gender and Race In the Labor Market, and Professor Marianne Bertrand of the University of Chicago in a study coauthored with Professor Kevin Hallock of Cornell. Single women between 25 and 35 earn more than single men of the same age, according to the Bureau of Labor Statistics.

Feminists are calling for passage of the Paycheck Fairness Act, a bill sponsored by Senator Barbara Mikulski (D-MD) and Rep. Rosa DeLauro (D-CT) that would insert the government into firms’ compensation decisions. Among other provisions, it would require women to opt out of class action suits rather than opting in, as is the case at present, which would be a boon to trial lawyers. It would give the government broader powers to collect data on wages by race and sex in order to be able to track compensation decisions. The Paycheck Fairness Act did not even pass in the 111th Democratic Congress in 2009-2010 in the first two years of President Obama’s term.

A choice of more leisure and less work is not a societal problem. If a doctor took off every Wednesday afternoon to play golf and earned 10 percent less, no one would call for government action. But when women decide to work less, as do many women, feminists call for passage of the Paycheck Fairness Act. According to the National Women’s Law Center, “supporting the Paycheck Fairness Act means closing the wage gap for working women.” This is only true if women make the same choices as to fields of study, jobs, and hours of work.

America has laws to protect women against discrimination. The law says equal pay for equal work. Women sue, and sometimes win. But the example of Maria Simon and Rebecca Geller shows that women’s earnings are often the product of rational choice, not discrimination.