Open-access science journal PLoS Biology has published an article by biologist Peter Lawrence where he suggests that the under-representation of women in science is not because they are biologically unsuited to scientific thinking (as some have controversially suggested), but because employers undervalue those attributes more likely, but not exclusively, to be present in female researchers.
Here I will argue, as others have many times before, that men and women are born different. Yet even we scientists deny this, allowing us to identify the “best” candidates for jobs and promotions by subjecting men and women to the same tests. But since these tests favour predominantly male characteristics, such as self-confidence and aggression, we choose more men and we discourage women. Science would be better served if we gave more opportunity and power to the gentle, the reflective, and the creative individuals of both sexes.
Link to ‘Men, Women, and Ghosts in Science’.
Mind Hacks 
Or perhaps it would help if we just stopped referring to self-confident, aggressive women as “bitches”.