Too much Soy may increase estrogen Levels in Men

There are now scientific studies showing that men who consume more than 25 grams of Soy (Milk, Tofu, etc.) per day are at risk for increased levels of estrogen that may cause gynecomastia(enlarged breasts) and other 'feminzation' characteristics, including reduced libido. Countries such as Israel, France, Australia, and New Zealand have actually recommended that Soy protein not be used in infant formulas unless lactose intolerance is present.

That said, Soy has also been shown to reduce the incidence of prostrate cancer and heart disease. Bottom line, if you are a man, limit your Soy intake to 25 grams/day.