A friend of mine is a female PhD candidate in astrophysics, a predominantly male field. She entered graduate school expecting sexism and harassment, and unfortunately that expectation has in large part been borne out. However, one reason why she has been able to endure it is an effort on the part of male astrophysicists--many of them strangers--to intervene when they noticed she was being harassed.

One example: while meeting a research group at a post-conference social, a postdoc 10 years her senior put his arm around her. Some turned a blind eye, others were mortified yet inert, but one man got up and asked the postdoc to switch seats with him. The outcome? My friend was spared having to spend her (already scarce) social capital on wiggling out of this dude's arm, some of her faith was restored in the men in her field (reducing the odds she'd eventually quit it entirely), the dude was sent a signal that his behavior was not okay, and the intervener lost nothing for his courage.

For us males in male-dominated fields, it is critical that we be mindful of when the non-males we are interacting with are being discriminated against or harassed, and more importantly, that we do something when we notice it. It could be as dramatic as something in this article, or it could be as small as apologizing to the non-male coworker you spoke over or saying that you see the sense in a non-male coworker's idea when it seems like it might be getting criticized more for its creator's gender than its merits.