To the Editor: Greenpeace, having succeeded in terrorizing Europeans about genetically modified (GM) food ingredients, is now flexing its muscles in the United States.(Gerber Baby Food, Grilled by Greenpeace, Plans Swift Overhaul; July 30,1999) Its target is not really food manufacturers, but American parents of infants and young children. Unfortunately, Greenpeace will likely succeed in frightening parents about ingredients they don't know about. There is no evidence that GM soybeans and corn in dry baby cereal have ever hurt anyone, and companies that have to rely on scarcer supplies will have to charge more for their products.