The Medical advantages were obvious. We have got bacteria to carry the gene for human insulin and so have an ample supply of human insulin for treatment of diabetics. Vegetarian renin for making cheese is obtained from bacteria that have had the renin gene from calves transferred into them. Research is developing bacteria to produce human interferon, growth hormone, cytokines, and a large variety of important complex compounds for the treatment of diseases. Human genes have also been put into sheep and goats so that their milk will contain a blood clotting factor that can be extracted and made available for the treatment of haemophilia.
Many plant leaves contain substances distasteful to insects.
Attempts are being made to transfer the genes responsible for these compounds into wheat and other plants so that the leaves will contain these compounds and it will not be necessary to use insecticides to protect the growing plant. Often it is not possible to distinguish food containing the soya that has this treatment from food with non treated soya. This can be solved by compulsory complete food labelling. In the development of gene transfer foods, the foods are fed to a range of animals for several generations to study their effects on animal health, growth, and reproduction. Then they are fed to human volunteers.