Modificeret soja har for eksempel fremkaldt allergi hos dyr, og majs med tre modificerede gener, hvoraf den ene er giftig for viklerlarven, hvorfor man endda risikerer, at dette insekt bliver mere modstandsdygtigt og breder sig.
Thus modified soya has led to allergies in animals and modified maize has three genes, one of which, being toxic for the European corn borer, could quite possibly lead this insect to develop greater resistance one day and to proliferate.