Soy contains substances called isoflavones (specifically genistein and daidzein) that are similar to the hormone called estrogen. These “phyto-estrogens” (meaning “plant-based estrogens”) are much weaker than the actual hormone – in fact, they have only about 0.1% the activity. Soy has been used for years as an alternative therapy for menopausal hot flashes – so there does seem to be a mild hormonal effect in people that already have an estrogen imbalance. But in babies taking soy, I rarely ever see any signs of hormonal imbalance. For older children and adults, I believe the health benefits (decreased risk of certain cancers, heart disease, etc.) of