If you want to know more about soy's hormonal effects you can follow the tag....I've done some of my own finding out about it. Soy isoflavones are mildly estrogenic, and taken in small amounts are unlikely to do anything other than make a woman's PMS worse and a man's fat deposit a little more over the pectorals. Large amounts can have different effects, and tends to have more effect on men than women because their natural estrogen levels are lower.