Physics is one of the fields which remains male-dominated, despite the fact that roughly half of all high school physics classes are women. The reason women don't complete physics bachelors degrees at the same rate as men are sometimes subtle, and no one solution will fix the problem. For more information on the data, have a look at The American Institute of Physics reports on women in physics.
I am serving on the American Physical Society Committee on the Status of Women in Physics (CSWP). The CSWP provides many resources to learn about and support women in physics.
Last update: April 2, 2015