1.   But progesterone can cause depression and spur fibroid growth, as estrogen does.

2.   Just two weeks ago, researchers reported that estrogen did nothing to slow the progression of heart disease in women whose arteries had already been partly blocked by it.

3.   Tamoxifen, for example, does reduce cardiac risk, but not to the extent that estrogen does.

4.   The big advantage, researchers say, is that it seems not to stimulate breast tissue, as estrogen does.

5.   We all know what estrogen does for a female.

6.   That is what the estrogen does to the bone cells.

7.   The work also suggested that estrogen does this by making other cells produce a substance called transforming growth factor beta.