As news of his death spread through Twitter, his peers called him a “singularity,” a “titan,” and a “moral compass,” who leaves behind a “towering legacy of goodness.” They spoke of unprompted acts of meaningful kindness. “I knocked on his door as a first-year and Ben Barres stayed an hour late to give me advice about women and medicine,” said Natalia Birgisson, a medical student at Stanford University. “I once invited Ben Barres to speak to young LGBT scientists. I sent the email at 11 p.m. and he responded in 10 minutes, agreeing to speak and refusing the honorarium,” said Trevor Sorrells from Rockefeller University. “I interviewed for grad school with Ben Barres and he stopped mid-interview to call another school and advocate on my behalf,” said Alycia Mosley Austin from the University of Rhode Island. As Kay Tye from MIT succinctly said: “Ben Barres was a role model for role models.”

Beyond direct mentorship, Barres repeatedly spoke up for groups who have been historically marginalized in the sciences, including women, minorities, and LGBTQ+ people. He would repeatedly talk about the biases and systemic barriers that keep such groups from succeeding in their careers, often raising the topic in the middle of keynote talks about glia. “Since I have you all trapped on the top of this mountain ... I would like to talk about the many barriers women face in science,” he once told neuroscientists at a conference in Lake Arrowhead.

He most famously talked about those barriers in a searing 2006 opinion piece, published in the prestigious journal Nature. In it, he lambasted several academics for suggesting that “women are not advancing in science because of innate inability,” and spoke of the actual reason for their hindrance: discrimination, both conscious and unconscious.

Barres amassed data and evidence to support his stance, but he also spoke from experience. Born in 1954, he transitioned in 1997 at the age of 43. Before then, as an MIT undergraduate, he solved a hard math problem that had befuddled the rest of his virtually all-male class, only for his professor to suggest that his boyfriend must have done the work. As a Ph.D. student, he lost a fellowship competition to a male peer who had published a sixth as many papers. And as a Stanford professor who had recently transitioned, he heard a faculty member say, “Ben Barres gave a great seminar today, but then his work is much better than his sister’s.”

“By far, the main difference that I have noticed is that people who don’t know I am transgendered treat me with much more respect,” he wrote in Nature. “I can even complete a whole sentence without being interrupted by a man.”

By openly writing about his experiences, Barres made it easier for other female academics to talk about sexism. “As a woman in science, everyone has this feeling that something’s not right, but it’s hard to put that into words in a way that’s compelling to men,” says Carolyn Bertozzi, one of his colleagues at Stanford. “Ben was one of the few people who did the control experiment—what would have happened in a parallel universe where you changed just one variable. [His experiences] were harder for other men to deny.”