Expression in the milk of a mammal, such as a cow, sheep, or goat, is a common application, as milk production is plentiful and purification from milk is relatively easy. Hamsters and Rabbits have also been used in preliminary studies because of their faster breeding. Conventional production methods for pharmaceutical proteins involve substantial investments of both time and finances. Not only are there manufacturing challenges involved with conventional production methods, plant-made pharmaceuticals could save substantial time, money, and provide a system for producing proteins that could solve current production challenges. One approach to this technology is the creation of a transgenic mammal that can produce the biopharmaceutical in its milk (or blood or urine). Once an animal is produced, typically using the pronuclear microinjection method, it becomes efficacious to use cloning technology to create additional offspring that carry the favorable modified genome.[1] The first such substance approved for therapeutic use was biosynthetic 'human' insulin made via recombinant DNA technology. Sometimes referred to as Biopharming, is a sub-sector of the biotechnology industry that involves the process of genetically engineering plants so that they can produce certain types of therapeutically important proteins and associate molecules such as peptides and secondary metabolites. The proteins and molecules can then be harvested and used to produce pharmaceuticals. Pharming in plants Controversy over pharming Biopharmaceuticals are medical drugs (see pharmacology) produced using biotechnology. They are proteins (including antibodies), nucleic acids (DNA, RNA or antisense oligonucleotides) used for therapeutic.