For example, researchers have developed transgenic animals such as cows and sheep that secrete economic quantities of medically important hormones or other active proteins into their milk. The cost of these drugs may be much less than for those produced using conventional techniques or even in microorganisms. Eventually it may also be possible to develop crops for non-food uses by modifying the starches and oils they produce to make them more suitable for industrial purposes, or to use plants rather than animals to make antibodies for medical and agricultural diagnostic purposes. In the cut flower industry, transgenic research has yielded new products such as blue carnations, which have been on the market since 1996. A blue rose is also planned.
Transgenic technology is still experimental and is still very expensive.
However, it offers a number of advantages over traditional methods. The number of additional unwanted traits can be kept to a minimum. Much current research focuses on the understanding and developing useful promoter sequences to control transgenes and establishing more precise ways to insert and place the transgene in the recipient. Much still needs to be done to improve our knowledge of specific genes and their actions and of the potential side effects of adding foreign DNA and of manipulating genes within an organism. Some people fear that widespread use of plants and animals with altered genetic characteristics may threaten the environment by disturbing the existing balance between organisms.