I do, for two reasons. First, I think that the cycle of a woman, compared to the stable levels of a man, are one of the major differences between the sexes. To quote Harry Chapin, "He was the sun, she was the moon." The sun burns at a constant level, while the moon goes through phases.
I also have a theory that fluctuating hormone levels are a key element of breast growth. In normal females, breast growth occurs during puberty, when fluctuation is at its greatest. The body develops resistance to chemicals. One way to limit this resistance is by varying the levels of exposure. For example, it has been proven that the natural medicine echinacea is most effective when taken at high doses for a while, then low doses for a while, before ramping back up to high doses.