The head of the National Institutes of Health announced Wednesday that he would no longer appear on all-male panels at public scientific meetings, saying the effort to include women and other underrepresented people “must begin at the top.”

In a statement released by the NIH, the nation’s premier biomedical institution, Director Francis S. Collins said “it is time to end the tradition in science of all-male speaking panels, sometimes wryly referred to as ‘manels.’ ” He added that if “attention to inclusiveness is not evident in the agenda, I will decline to take part,” and challenged other scientific leaders to do the same.

Collins speaks about 125 times annually, according to the NIH, often as a keynote speaker but sometimes as part of a panel. His announcement is more important as a signal that one of the world’s top scientists is addressing the issue, according to an activist working for women in science.

“Just to introduce this little bit of friction into the way we think of what an invitation means, and what it means to be included, is a very powerful message he’s sending,” said Maryam Zaringhalam, a member of the leadership team at 500 Women Scientists, which works for inclusion of women, minorities, members of the LGBTQ community and others in scientific leadership roles.

Zaringhalam said she hoped Collins’s statement would prompt men invited to speak at scientific meetings to ask whether underrepresented groups would be included and to suggest people who might fit the bill. In some cases, she said, men might suggest their own replacements.

Wednesday’s statement is the second time in the past year that Collins has formally addressed the treatment of women in science. In September, he voiced concern about sexual harassment, saying “it presents a major obstacle that is keeping women from achieving their rightful place in science,” and pledged greater effort to combat it at the NIH.

On Wednesday, Collins cited a 2018 report by the National Academies of Sciences, Engineering and Medicine that, he noted, “identified the critical role that scientific leaders must play to combat cultural forces” that allow harassment and limit women’s advancement.

With a $39.2 billion budget from the government, the NIH is the world’s largest public funder of biomedical research. More than 80 percent goes out in the form of grants to 300,000 researchers in the United States and around the globe. Another 10 percent funds 6,000 researchers in the NIH’s 27 institutes and centers, mainly in Bethesda, Md.

Across the United States, women hold 45 percent of tenure-track faculty positions in biomedicine, 29 percent of the tenured faculty jobs and a smaller number of leadership positions, according to a 2017 report on workforce diversity by an NIH panel. Yet women earned more than half the doctoral degrees in the biological sciences over the previous decade, the report showed, providing a ready pool of people able to fill such jobs.

At the NIH itself, the numbers were worse, with 22 percent of tenured faculty jobs held by women, along with 38 percent of tenure-track jobs.