Why do women (and men) leave academic science (pre-tenure)?
1. Science is not for everyone. It requires grit, stubbornness, ability to think strategically, thick skin, and passion.
2. Financial side: salaries for post-docs are decent (enough to live comfortably as long as you don't live in a super-expensive area and don't have expensive hobbies/multiple kids; if you do have kids, it helps to find affordable childcare or rely on family/spouse for childcare). However, lets face it: you could make MORE money elsewhere.
3. Funding: it is very tight and it is not getting better in the near future*. It is really, really hard to get grants for your research (not impossible... just HARD). There has been a fundamental paradigm shift, with universities getting research money from pharmaceutical companies. On one hand, this is a wonderful opportunity for a number of labs (since the government money is drying up). On the other hand, there are plenty of caveats here.
I can't help but wonder about the projects that end up being dropped... Pharma is going to fund projects that they hope will make them money. Novel therapeutics, novel drug targets for big-name diseases, novel medical devices. NIH grants also tend to favor disease-based applied science. What about all other science? Not the targeted science (lets find cure for XYZ), but the fuzzy, open-ended science. The "science for the sake of science" that is meant to help us understand how things work, be it on the protein, cellular, or whole-animal level? I am afraid that in our race to find novel ways to treat disease, we may miss some fundamental facts. In the long-term, that is going to be crippling to the scientific progress (and prevention/treatment of disease).
4. Health. Working with carcinogens, radioactive materials, foul chemicals - long term can add up to health issues. We all tend to get sloppy...
5. Work environment: egotistical, screaming colleagues who like to take all the credit (if you are really unlucky, that's your boss).
To be fair, I've been extremely fortunate to have good mentors and to work with amazing scientists who had integrity, sense of humor, and willingness to share their knowledge and expertise. With one exception, I am so glad I got to know them!
There are countless reasons why different people would leave academic science and start a new career... It may have been an agonizing decision or the only way forward. One way or another, for many of us, it was time to move out (of the lab) and move on.
*Some of my colleagues ended up leaving the country instead of changing career paths. One, a brilliant crystallographer, got a professor positions at Nankai University (China). Another, a neurobiologist, got a position at the University of Seoul (Korea).