[Tim Sharp]

That sounds good in theory, but is problematic in practice. If I were to insist that certain members of the team participate in something other than their favored area while others are allowed to work on the team of their choice, I would soon find myself on the receiving end of a "favoritism" charge (this is not conjecture, it's happened).
What would I tell a student when confronted with the situation? "You can't do what you want like everyone around you, because you're a girl"?
It comes down to a choice. Do I dictate how everyone participates, or do I allow them to choose. In my opinion, a more productive and harmonious environment is achieved by allowing everyone to match their interests to their contributions. This, in my opinion, allows students to develop a sense of ownership in the project, which is the real key to unlocking potential.
Not to say that I haven't moved students around when the need arose. However, when I did there was always a clearly articulated reason for it and little room for argument that it was done for any reason other than what was good for the team. It is also understood that the younger members of the team will have less autonomy as to their designation (but not none), and earn the right to choose their specialty as they gain experience.

I would also argue that the girls on the CAD, Controls and Electrical team are as deeply embedded in STEM as anyone on the team. They are certainly cut no slack and are expected to contribute as equals. And they do.