In the US, women were officially barred from long-distance running, like marathons, for decades due to false medical myths, such as the belief that running would cause harm to the uterus or that they were physiologically incapable of enduring 26.2 miles.

Authorities, including the US Amateur Athletic Union (AAU) and Olympic founder Pierre de Coubertin, argued that running could cause infertility, uterine damage (including the false idea that the uterus could somehow “fall out”), or loss of femininity. These beliefs were used to justify excluding women from competitive sports, reflecting broader societal fears about female independence and gender roles.

The AAU explicitly prohibited women from competing in road races longer than 1.5 miles, and the Boston Marathon effectively banned female participation until 1972 when the first official women’s race was held.

Boston marathon race directors like Will Cloney claimed women were not “physiologically able” to run 26.2 miles, citing concerns over “medical liability.”

Despite these bans, Bobbi Gibb became the first woman to run the Boston Marathon in 1966 by sneaking into the race in disguise, and Kathrine Switzer became the first officially registered female competitor in 1967 by entering under the name “K.V. Switzer.”

Switzer’s race was interrupted when race official Jock Semple attempted to physically remove her, but she was protected by both her boyfriend and her trainer and finished the race. The event sparked international attention and eventually led to rule changes.

Before 1972, women were not allowed to have their race times recorded in the Boston Marathon, and the AAU banned women from competing against men after Switzer’s 1967 run, though this was later reversed.

No legitimate medical studies supported the claims that women were unfit for long-distance running. The bans were based on pseudoscientific myths and cultural biases, not empirical evidence.

Today, the myths have been busted, and the landscape has shifted dramatically, with women making up approximately 40% to 45% of marathon runners.

Boston marathon 2026

Ahead of the 2026 Boston marathon, April 20th, the current registration numbers are:

• Men: 18,277 entrants (56.3%)
• Women: 14,101 entrants (43.5%)
• Non-binary: 116 entrants (0.4%)

These figures reflect the final entered field of 32,494 athletes, with 30,000 expected to run on race day.