I listed it in the basic concepts list, but as part of the recent drive by science bloggers to post on basic concepts in their field, Zuska of "Thus Spake Zuska" has an excellent post on Feminist Theory of Science. It is well worth reading. Zuska also mentions Helen Longino, who is likewise well worth reading.
Thanks to the magic of the internet, by the way, you can listen to Helen Longino discussing truth and relativism; you can read the transcript of an interview with her; you can also read one of her speeches for an Evelyn Fox Keller celebration.
I once wrote an essay defending Longino's view that scientific practice is not value-free by pointing out that everyone in fact recognizes that this is true when it's convenient for them; but it's also common practice to dismiss the claim when convenient, as well. There are few areas in which the dismissal comes so readily as when feminists start noting gender-related flaws in current scientific practice. Everyone shrugs their shoulders and says something like, "Of course our ideal is to have parity in such-and-such field; but the fact that we don't doesn't change the basic way science works" -- completely ignoring, of course, facts such as the shockingly common shortchanging of women in medical research by generalizing results from all-male test subjects to women without considering differences in body chemistry. When these flaws are detected the scientific work is obviously better; but the improvement is not recognized as due to the elimination of a gender-related flaw, but simply shoved into this vague, quasi-mystical phrase, "the way science works," into which too many scientists have a bad habit of retreating whenever they don't want to address a problem. Fortunately this has been changing for a while, in great measure through considerable persistence on the part of feminists.
One of the difficulties a feminist theory of science faces is that there is indeed a sense in which 'science works the same' whether feminist concerns are addressed or not; measurement is still measurement, mathematics is still mathematics, experiments are still experiments. One thing that has helped me to recognize the importance of a feminist theory of science is to see that merely because 'science works the same' in this limited sense doesn't mean that it's working equally well. It will be the same in kind; but not the same in quality. Compare the difference between being a scientist in a genuinely free country and being a scientist in an oppressive regime. The free country and the oppressive regime may both put quite a bit of emphasis on the particular scientific field in question; but (for instance) oppressive regimes can meddle as they see fit, whereas the governments of free countries are sharply limited as to what they can do in this direction. One is clearly better for 'the way science works'. Nazi medical research is tainted not only ethically but also because it can't be trusted: there's too much agenda there, and, what's worse, it's an agenda that is irrational. What feminist theory of science is concerning itself with is the question of (putting it crudely) how to make science work better -- that is, how to have better quality research and education of the same kind. This is not a minor or insignificant issue, and it's not an issue that can be shrugged off. The case, of course, is not quite so cut and dry as the other examples I've given; feminist theorists of science are dealing with a much more complex and tangled problem, and so usually have to work with scalpel rather than hammer and chisel. But the point is the same: science doesn't 'work' on its own; it is something done under various conditions, some of which are more favorable to its being done well than others. What we usually call science is a community effort, and there are aspects of that community effort that thrive under some conditions but not under others. Many of those aspects are related to issues examined by feminists. Thus the need for a feminist theory of science.