If this is true wouldnt' you expect to see lots of nice lean post-menopausal breast cancer patients as well??
From some of the discussion I've seen I think that nolva really doesn't work so great at higher bodyfat levels. Note I'm not a doc, but we have to keep in mind that nolva & guys isn't the same as nolva & girls.
http://www.elitefitness.com/forum/showthread.php?t=385496&highlight=nolva
The bottom line is that there is still a lot of research around understanding hormones in the female body. Most of the research around estrogen manipulation is related to post-menopausal women, not young, healthy female athletes. Unless you are in a competition situation both from an experience stance and also from the point that you only expect to look a certain way at a certain time of day on your competition day and not as a generally maintainable level of leanness, should you even bother getting involved w/ hormone manipulation. Your choice -- for everything discussed on boards like these, especially for women - you are your very own personal petrie dish. Knowledge is power and the final decision, results and sides lie w/ you.