protein- muscles, and soy.....?

I read in one of the other forums here that soy milk is not recommended. could you please elaborate. I drink a lot of soy milk (chocklate flavored)and ahve a lot of soy protein rich oatmeal cereal. if i start depending on protein suuplemets, will there be any adverse effects on the muscles (if i do mange to build some) if I quit the supplements? I am 30- female and a vegan with Acne problems too. Tweet