Others have commented in this thread how gender-biased attitudes towards engineering fields are present even in young children. There's an obvious connection between this and the fact that when you're a child most of the adults you met in your everyday life practicing technical jobs (plumbers, cable technicians, car mechanics) are male. On the other hand, children see how their pre- and middle- school teachers are mostly female. Thus, children learn by observation that technical job => male.
Yes, neither car mechanics nor pre-school teachers have prestigious, 6-figure salary, PhD level positions, and yet they have a big impact in the perception of gender bias in adult labor when children are growing up and unconsciously cementing their views of the world.
I believe that a big step to close the gender gap in engineering would be young girls watching the super cool woman in the car shop expertly fixing daddy's car.