Scientific researchers have figured that foundational breast type tissue growth occurs most efficiently with the balanced presence of estrogen, progesterone, prolactin, prostaglandin's, and GF compounds (human growth factor hormones). Improper balances of those hormones, along with other complications, result in insufficient breast development. At some point after adolescence, our bodies ceases to produce GF compounds, producing a completing breast tissue growth. Thus, phytoestrogens that mimic hormones effects allows you stimulate breast growth again. If you quit each time, at least you are doing something to avoid getting pregnant. But couples that rely only on sexual intercourse do tend to get pregnant.