Guido van Rossum is one of the world’s most influential programmers. Van Rossum is the author of the general-purpose programming language Python, which he started working on in 1989, and is now among the most popular languages in use. According to a survey of users on Stack Overflow, a popular question-and-answer site for programmers, Python is the fastest-growing major programming language, and the most used after JavaScript. Python is free and open source, meaning anybody can use the language and modify it to suit their specific needs.

In addition to creating the language, van Rossum has overseen its development. Programming languages evolve over time, with changes made to add features and fix bugs. Modifications to the official version, generally suggested by active users of the language, go through a complex approval process managed by a founder or core development team. Van Rossum served as the “benevolent dictator for life” of Python’s development until last year, when he stepped down from the post.

As Python grew in popularity, van Rossum noticed a problem.

In a rare interview with the programmer in October last year, which was recently published on YouTube, he was asked about the lack of diversity among the people working on open-source programming languages. He noted that it was an issue, and said that those who ignore it, because open-source projects are available for anyone to contribute, are not seeing the full picture.

“It’s not just joining a project that’s the problem, it’s staying in the project, which means you have to feel comfortable exchanging emails and code reviews… with people that you don’t know personally but you communicate frequently with online,” he said. Van Rossum thinks that these exchanges can be difficult for women because of unconscious bias and male-driven cultural norms within open-source communities.

“It’s not just about writing the code, but you have stand up for your code and defend your code, and there is a certain male attitude that is endemic in many projects where a woman would just not feel comfortable claiming that she is right,” he explained. “A guy who knows less than that woman might honestly believe [he is right], so they present a much more confident image.” In his experience, van Rossum sees incompetent men’s ideas gaining acceptance more often than merited because they are more forceful in how they present them.

Van Rossum believes that the different attitudes of women and men in programming communities is due to wider societal problems that we need to fix from the bottom up. “I’ve always felt that feminism was right and we need to change the whole society,” he said. In the meantime, he feels a responsibility to act in the places he has influence, like in the Python community.

He believes the key to making open-source communities more inclusive is establishing (and enforcing) codes of conduct and mentoring. Van Rossum says that he now mentors women and underrepresented minority programmers. “But white guys can forget it,” he said. “They are not the ones who need it most.” (In typical programmer speak, he calls mentoring a “completely distributed, democratic approach.”)

Rather, he thinks it’s important that men are educated about their biases. “[There are] some guys who are super defensive when you tell about this shit, but the majority of guys just don’t know any better,” he said. “The first time I heard the term unconscious bias was maybe five years ago and it was an eye opener.” It’s changed him, and he thinks it could change others.

You can watch the interview, with the writer Swapnil Bhartiya of the coding-focused website TFiR, below. The discussion about diversity occurs around the 23-minute mark: