Final answer:
Women were not allowed to run in the Boston Marathon until 1972 due to misconceptions about their physical abilities and concerns about their reproductive health. The belief that women were not capable of running long distances was disproven by women like Kathrine Switzer who challenged these beliefs and paved the way for female participation in the marathon.
Step-by-step explanation:
Women were not allowed to run in the Boston Marathon until 1972. The decision to exclude women from the race was based on misguided beliefs about women's physical abilities. It was commonly believed that women were not capable of running long distances and that the physical exertion of a marathon could harm their reproductive organs. However, women like Kathrine Switzer challenged these beliefs and paved the way for women to participate in the marathon.