And it wasn’t even supposed to really matter.

Title IX of the Education Amendments of 1972 had a simple goal: to end sex discrimination in schools that receive federal money. Had the ERA passed, however, it wouldn’t have even been needed. But as approval of the constitutional amendment stalled in the states, Title IX became the law that endured—and made a difference.

Edith Green, a congresswoman from Portland, began working on the law in the early 1970s. Nicknamed “Mrs. Education” for her many years of work on higher education, she was appalled to learn that public schools could create special programs for boys that excluded girls. At the time, girls were often discouraged from taking advanced math and science classes, female teachers rarely became principals, and many law schools and medical schools had quotas that kept women to no more than 10 percent of the class.

All she wanted was for girls and women to get a fair deal. But over and over, her male colleagues told her, women just want to stay home and raise families. Men need those opportunities, but women don’t.

Although the language of Title IX addresses sex-based discrimination in education on a very broad level, the most widely lauded changes have occurred in the area of athletics. To a certain extent, academic gains have not occurred on par with athletic gains. Yet even within collegiate sports, women still have fewer participation and athletic scholarship opportunities than men, and far fewer immigrant, minority, and women from low-income families play sports than middle-class Caucasian women. Access to competitive women’s sports is not yet equal.

In the classroom, while female students demonstrate greater success than their male counterparts by certain measures, boasting higher GPAs and graduation rates, women are still underrepresented in STEM fields. The academic achievement gap has narrowed in many important ways, but the STEM gender gap remains a particularly recalcitrant problem. In a global economy driven by technology and innovation, men still hold the most prestigious, highest-paying jobs by a large margin. The jarring lack of women in scientific, technical, or other nontraditional professions—defined as an occupation in which less than 25 percent of the workforce are women—was not fully addressed until 2000, 30 years after the passage of Title IX, when the National Science Foundation and the Department of Energy performed their first on-site compliance inspections.

In academia, Title IX compliance with regard to STEM education has likewise been slow to take hold—women are 25 percent less likely to attain full professorship than men, and make up only 19 percent of full professors in these fields as of 2006. Marked differences in advancement across diverse fields also prevail. Although female representation in the social and life sciences has climbed steadily since Title IX passed, progress in mathematics, physics, and engineering has remained stagnant over the last decade, and has even declined in computer science in recent years.

The slow progress in STEM fields has been attributed to a number of factors, including pervasive cultural biases and gender stereotypes, and hiring, promotion, and tenure-track practices that penalize pregnant women and female caregivers. There are deeply entrenched cultural beliefs about gender differences in intelligence, ability, and interests. These beliefs impact female identity and academic performance at every stage of one’s education, from preschool to postgraduate work. Biology, for instance, is seen as a largely gender-neutral subject requiring no special “innate” talents in math and science, whereas computer science and engineering are considered “male” fields. Such assumptions are both the result of and result in unequal representation in critical fields and leadership positions, creating a self-reinforcing negative feedback loop. Women, even when they have attained high levels of success, may present their achievements in social situations very differently from men potentially to their own detriment. Princeton’s 2011 report on undergraduate women’s leadership found that “women consistently undersell themselves, and sometimes make self-deprecating remarks in situations where men might stress their own accomplishments.”

Eleo Sears was condemned from pulpits and town squares for wearing trousers that gave her the ease of movement to compete effectively in the sports she loved—and, she concluded, if such attire infuriated the moral arbiters of her day, then so much the better. She honed her innate talent and, with refreshing humor and a firm refusal to take “no” for an answer, she became the first woman to play polo on a men’s team. She became a five-time national doubles tennis champion and the first female national squash champion. She convinced Harvard officials to open their squash courts to other women players; she founded the Women’s Squash Racquets Association, and she coached the U.S. Women’s International Squash Team. She was also a long-distance swimmer; she boxed and played golf; she ice-skated; was a crack shot with a rifle, and raced yachts. She excelled in 19 different sports, making her America’s most versatile female athlete.

If you ever wanted to see Eleo spring into action, you just needed to bet against her. Such a bet in 1912 set her off on a 110-mile hike down the California coast. Other bets in later years sparked a series of record-setting hikes between Boston, Newport, and Providence, which gained her national attention and inspired walking contests among men and women across the country. The New York Times, in a 1925 editorial, praised Eleo as America’s valiant pedestrienne who was perfecting “the one universal art to save the world from physical degeneracy.”

Eleo’s tradition-shattering exploits were not confined to sports arenas. She was one of the first women to fly an airplane and drive an automobile, and in 1909, she became the first woman on record to fight a speeding ticket. She explored the ocean’s depths in a submarine. Clearly not a woman to shy away from controversy, she got herself arrested in 1910 for smoking in the lobby of Boston’s Copley Square Hotel, not because she had any fondness for cigarettes, but because women were prohibited from smoking there, while men could do so undisturbed.