I found this article a while back, but I feel as though it’s one of those ongoing topics always worthy of being discussed.
I’m always a sucker for tests such as one of the ones they ran:
“To assess identity threat, the researchers measured the participant’s physiological arousal during the video, cognitive vigilance, sense of belonging and desire to participate in the conference.
The results are telling. The women who watched the gender unbalanced video- where women were outnumbered by men in a 3 to 1 ratio- experienced faster heart rates, higher skin conductance (sweating), and reported a lower sense of belonging and less desire to participate in the conference.”
Check out the full article here:
http://www.physorg.com/news110550785.html
Note about this image: Found it via google search for “engineer.” This picture was tagged as “Clay County Engineer.” The woman is the office manager. 
