Gender Gap in Science: Freedom to say "No" ?

Why aren’t there equal number enough women in hard science and engineering? Larry Summers, the President of Harvard and ex-Treasury Secretary, got in trouble when he tried to suggest an answer. So the controversy hasn’t exactly died yet.

But could the reasons be because women simply choose differently? Here’s an article in Boston Globe that quotes two researchers.

Now two new studies by economists and social scientists have reached a perhaps startling conclusion: An important part of the explanation for the gender gap, they are finding, are the preferences of women themselves. When it comes to certain math- and science-related jobs, substantial numbers of women - highly qualified for the work - stay out of those careers because they would simply rather do something else.

Read for yourself and form your own conclusions.

My question is: Must there be gender equality in every profession or sphere of life?