Apr. 13, 2021 , 3:25 PM The U.S. National Academy of Sciences (NAS) is moving for the first time to expel sexual harassers from its membership. Science has learned that the institution is adjudicating complaints that could lead to the ejection of astronomer Geoffrey Marcy and evolutionary biologist Francisco Ayala. The process is unfolding 2 years after the prestigious, 158-year-old academy changed its bylaws to allow expulsion of members. Until then, membership had been for life. Rescinding membership is the most drastic penalty under the new rules, which also allow for lesser sanctions. With the potential moves against Marcy and Ayala, “We are watching social change happening in front of our eyes,” says Nancy Hopkins, an NAS member and emeritus biologist at the Massachusetts Institute of Technology. “It has been a long time coming.”