5.20 Evaluate the potential for using cloned transgenic animals, for example to produce commercial quantities of human antibodies or organs for transplantation.

As mentioned, one use of cloned, transgenic animals (meaning they have had another organism's DNA inserted into them) is to produce commercial quantities of human antibodies or organs for transplantation. Some examples include:

• Cows with medicine in their milk can be cloned
• Pigs with human hearts can be cloned for organ transplant

Animals can be given genes to produce human antibodies, which can be later injected into humans to help them face infection, rather than allow the immune system to find the appropriate antibody (which would likely take much longer). 

Sheep and cows can be modified to produce human proteins in their milk, which makes it more beneficial for us.

Animals with organs similar enough to human ones can be used for transplants, which would significantly reduce the problem of shortages. However, this may be a problem for ethical reasons (i.e. it can be considered inhumane to breed animals only to cut out their organs)

There are advantages and disadvantages of the process:

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• Cloning can happen at any time of year (out of breeding season)
• Infertile animals can be cloned
• Desired traits can be passed on with almost 100% certainty

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• Cloned animals may develop problems 
• Cloning is a relatively new technology, meaning that it may have negative consequences that we are not aware of 
• Low success rate (many animals will die horrible deaths)
• Difficult, time-consuming and expensive