As someone who got her PhD in one the STEM subjects last year and is a postdoctoral researcher now, I can give you a few reasons why so few women decide to pursue a scientific career:
- The start as a scientist is VERY hard. You have no security of a job place for at least the first 10 years. Postdoc positions are limitted for 2-3 years so you need to apply for a new job every few years (and always hope that you'll get the next one)
- There are significantly more applicants than free positions: the ratio of >50 applicants for one job is quite normal.
- You have absolutely no choice as where you are going to get your new job. If it is in New Zealand, then you'll have to move to New Zealand, if it is in Alaska, then be prepared to buy warm winter clothes. Good luck with it if you have small children or want to start a family. Oh, and if your partner is also a scientist, then be prepared for a never-ending long-distance relationship.
- Be prepared to have a salary which is significantly smaller than e.g. in other jobs which require a university degree
- You are under constant pressure to produce results: an extended period of time without a publication which gets cited is your death as a scientist
- You need to grow a very thick hide. The field is exceptionally competitive so all your colleagues are going to find even the smallest fault with you and your work. Be prepared to get looked upon (not because you are a man or a woman but because other people will look better if they can make you look like an idiot) and to get aggressive remarks. Once you get your paper back from the peer-review, you'll start questioning not only your own abilities but the world as a whole.
- You need to become aggressive yourself and feel entitled to any money which you can apply for from any funding source. You'll need the money for your research.
- Do you like your home? Then you should stop doing it - not only will you move to another home in 2 years, but you'll be away from home a lot on conferences, meetings and symposiums. And be prepared that you need to fly a lot.
So, in view of all this, it is not really surprising that so very few women apply for it. Not because of any gender issues (in fact, I have never been pampered so much because I am a woman), but because the job is hard. At some point you have to decide whether you like to strive for some scientific ideals and ideas or whether you should stay down-to-earth, get a proper job with a decent salary and found a family. Oh, and just keep in mind that after the 10 years of your postdoctoral career, it is quite a large chance that you won't get one of the few professorships out there and that you'll need to start anew somewhere outside of science.
