Estrogens Estrogens are steroids . They are primarily responsible for the conversion of girls into sexually-mature women.
Estrogens also have non-reproductive effects.
They antagonize the effects of the parathyroid hormone , minimizing the loss of calcium from bones and thus helping to keep bones strong. They promote blood clotting. Progesterone Progesterone is also a steroid. It has many effects in the body, some having nothing to do with sex and reproduction. Link to a discussion of steroid response elements with a stereo view of a steroid receptor bound to the DNA helix of its response element.