One advantage of genetically engineered animals is that they grow faster and larger than natural animals, and they may produce more efficiently, according to Michigan State University Animal and Legal Historical Center. One disadvantage of genetically altering animals is that it decreases the genetic diversity of the species, making the species more vulnerable to new types of infectious diseases.
The ability to delete stress genes in animals and to make them non-sentient is one possible advantage of genetically engineering animals, notes Michigan State University. This renders the animal incapable of feeling pain, and potentially eliminates suffering imposed during an industrial life. Some might consider this a disadvantage, as it may make conditions in factories worse for animals and may increase their suffering. Proponents of genetic engineering also consider it immoral to rob an animal of its sentience.
Genetically engineered animals may better resist known diseases such as hereditary breast cancer, informs Michigan State University. This allows scientists to more accurately research certain diseases faster and less expensively. Another advantage is that scientists can genetically engineer animals to produce complex human proteins, which are used to create new therapeutic drugs. This method of producing complex human proteins is cheaper, easier to manufacture and mass produce, and may result in less sacrifice of animals than traditional methods.
Genetically altered animals may decimate wild populations of the same species if the engineered animals escape into the wild, states the Michigan State University. They may also harm the natural environment.