I am definitely not an expert on soy, but my dad is a vegetarian so i do know a little bit. Soy is a bean that is a good source of different minerals, vitamins, and also protein. My baby sister is lactose intolerant, so we give her chocolate soy milk to drink. I am guessing that it can't be too harmful, because she has been drinking it for over a year and she is the smartest kid for his or her age in our family. I personally am not a fan of any soy products, even if it is healthy.
My aunt owns a horse farm for race horses, and she told me a very interesting fact about soy that i never knew before. Horses cannot eat raw soy because it contains a chemical that will make the horses lose a lot of weight very rapidly. But once soy has been cooked, it is used in a great number of horse feeds.