GM soya beans. Genetically modified (GM) soya (Glycine max) has had a gene altered in the laboratory to make it resistant to chemical herbicides. This means that farmers can spray entire crops with herbicide to kill weeds, but the soya continues to grow, theoretically increasing yields. There is concern over the safety of GM foods, as well as the possibility of contamination of non-GM crops. Soya beans are a good source of dietary protein. They also provide most of the B- complex vitamins, and the essential minerals iron and potassium. They can be prepared in a variety of ways, for example tofu, and are used in many processed foods.