[snowwrestler]

The essential reason his original comment was sexist was that the only way it makes sense is if one assumes the default state of a lab is men only.

Basically, if your thought process is that women are an optional addition to a fairly normal human activity (scientific research in this case), you're going to be accused of bias. I mean, people said almost exactly the same things about women in offices, women in factories, women in the military, gays in the military, gays in the NFL, etc.

edit: clarity