Fewer women apply because there are fewer women in the field. It's that simple. If you consider that a problem, the author of the article is trying to solve it at the end of the road, when the solution lies at the beginning. The beginning is in school, and the problem is most certain sociological.

This is awful and it's frustrating to see. You have a job to fill and that job needs to be filled by a person. Gender imbalance in your work place isn't something that's up to you to solve. As a company you judge candidates based on merit, not gender! Be interested in hiring good employees, and if a woman applies and she's the best fit for the position, then hire her, but don't give her a leg up over a man because she's going to change some ratio.

If you hire a woman that is 50% as capable of another male candidate, that's asinine and you're an idiot.