Title IX was great for female athletes. And terrible for female coaches.

I once had a soccer coach who stalked the sideline in cowboy boots, snarling helpful commentary such as “Man up!” and “Don’t be a sissy!” When I broke my arm diving for a ball during practice, he asked if I was going to “cry like a girl” or get back in position. Being a 14-year-old girl, I cried.

I never played for anyone else who seemed to disdain girls quite like Coach Cowboy Boots, but he did have something in common with every other coach I had during 15 years of playing organized sports: a Y chromosome. From kindergarten rec-league soccer through two years of Division I college fencing, I never played for a female coach.

That puts me in good company. Female college athletes have never been less likely to have a female coach. The same trend holds in this summer’s Olympics: Of the five sports in which the United States is fielding a women’s team under a single head coach — basketball, field hockey, soccer, volleyball and water polo — only the soccer coach is a woman.

Surprised? After all, opportunities for female athletes have skyrocketed since Title IX prohibited gender-based discrimination in educational institutions 40 years ago this summer. More than 200,000 women play college sports today, compared with 16,000 in 1972. When the Olympics opened on Friday, the U.S. team included more female athletes than male ones for the first time.

And there’s the dirty little secret of Title IX: Female coaches have become a casualty of the same law that provided such huge benefits to female athletes. In 1972, more than 90 percent of the people coaching women’s teams were women. Today, that number is 43 percent, according to data compiled by two retired Brooklyn College professors who have tracked the number of female college athletes and coaches in the United States since Title IX became law.

The explanation for the downward trend is as simple as it is discouraging. By legitimizing women’s sports, Title IX bestowed a new level of respect — and significantly higher salaries — on college coaching jobs, transforming them from passion projects for the most dedicated women’s sports advocates to serious career paths. When she began her career at the University of Tennessee in 1974, legendary basketball coach Pat Summitt earned $250 a month. Before retiring at the end of last season, she drew a salary of more than $2 million.

As soon as salaries began to rise, more men became interested in jobs coaching women, says Judy Sweet, a longtime athletics administrator who became the NCAA’s first-ever female athletic director of a combined men’s and women’s program at the University of California at San Diego in 1975. Assistant coaches of men’s teams saw a chance to be promoted faster by applying to head-coach jobs on the women’s side. Job opportunities doubled for graduating male athletes who weren’t going pro but wanted to stay in the game. Athletic directors, whose ranks have always been overwhelmingly male, increasingly hired other men for open positions.

The result has been a consistent decrease in the percentage of female coaches. In 1987, the share of women’s teams coached by women dipped below 50 percent for the first time. Since 2000, men have been hired for more than two-thirds of open jobs coaching women’s teams.