Work done by American geneticist Barbara McClintock showed that genes could jump between DNA strands. Biologists can now transfer genetic information from one organism to another. For example, genes that produce a protein that stops deep-water fish from freezing in the Antarctic can now be put into transgenic tomatoes, potatoes, and tobacco, to make them more resistant to frost.
- The shadow of eugenics hangs over today's debates about genetic engineering and enhancement. Critics of genetic engineering argue that human cloning, enhancement, and the quest for designer children are nothing more than "privatized" or "free-market" eugenics. Defenders of enhancement reply that genetic choices freely made are not really eugenic-at least not in the pejorative sense. To remove the coercion, they argue, is to remove the very thing that makes eugenic policies repugnant.
- Sorting out the lesson of eugenics is another way of wrestling with the ethics of enhancement. The Nazis gave eugenics a bad name. But what, precisely, was wrong with it? Was the old eugenics objectionable only insofar as it was coercive? Or is there something inherently wrong with the resolve to deliberately design our progeny's traits? 
Opinions in favor of genetic engineering
Some people believe that modifying food crops to improve the vitamin content or make them resist drought or herbicides will provide the world with more and better food.
Genetically engineered bacteria can produce human insulin for diabetics. Scientists hope they will be able to use it in the future to cure DNA errors that cause illnesses such as muscular dystrophy and cystic fibrosis. Cures though, are not yet imminent.
Opinions against genetic engineering
Other people believe we know far too little about the consequences of altering plants in a way that is impossible in nature. They think it is too high a risk to let such plants loose in the environment where they might cross-breed with other plants and cannot be recalled if it is clear that the effects are harmful. There have been suggestions that one of the causes of the dramatic drop in the population of bees is the use in the USA of genetically-modified crops that are resistant to herbicides.
Many people are worried that if people are ever designed genetically, the human race could change in ways we cannot foresee. Most countries still have laws to prevent scientists researching genetic engineering in humans.