"In 1967, commentators told Katherine Switzer that her uterus would collapse if she competed in the Boston Marathon (she finished, and it did not). Women didn’t gain clearance to compete in all the track events available to men at the Olympics until 2008. As women demolished the cultural barriers to competition, Epstein writes, they swiftly gained on men, prompting some commentators to argue that they’d eventually outrun them. But their quickening pace soon plateaued, while male runners are still “ever so slightly pulling away.” Today, the male world-record holder in the 100-meter sprint is 10 percent faster than the female record holder. The fastest male marathoner also boasts a 10 percent advantage over the fastest woman. This gap is not exclusive to running: In speedskating, the gulf is 9 percent; in the long jump, it’s 19 percent; in weightlifting, it’s 25 percent. Epstein argues that these physical and ability differences shouldn’t be leveraged to make a cultural determination about the relative worth of men and women’s sports: “If we wanted simply to see the fastest runners, we could have cheetahs race instead of humans,” he writes. “We must be vigilant to ensure that all women who want to compete have the opportunity to do so, but the idea that women’s athletic performances must be equivalent to men’s in order to be deemed remarkable belittles the achievements of female competitors.”"