All food that is produced by humans through agriculture and farming has been genetically modified in some way, even though much of it happened in ancient times. Corn would cease to exist without humans. Almonds would all be poisonous. Cattle would not be docile. Wheat would scatter it's seeds before we could collect them. Man has been genetically modifying its food for thousands of years - even if we didn't always understand that's what we were doing. We actually understand the consequences of what we are doing far better than we ever did - because we are doing it consciously with science. This is what he discovered.