Have you ever see the movie Gattaca, one of the main premises of this movie is that most of the babies that are born are genetically screened for sickness, cancer, and disease. If a baby is found to have any genes that have the potential to cause any of these sicknesses they would be aborted. Babies that are born without this genetic screening process became known as 'God's children'.
This eventually lead to two classes of people in society. If you were born with the genetic screening, you got to be part of the elite. The God's children were only allowed to work menial jobs like: maids, garbage collectors, janitors, etc.
The TimesOnline has an article titled, "First baby in Britain designed cancer-free". Here is a brief excerpt from the article: "A woman is pregnant with Britain's first designer baby selected to prevent an inherited cancer ... Her decision to use controversial genetic-screening technology will ensure that she does not pass on to her child the hereditary form of eye cancer from which she suffers."
Human genetics is a very controversial technological subject. I believe one day it holds the possible promise of preventing and curing cancer and disease. The problem is the same technology can be used for more controversial matters, such as: human cloning, creating more deadly biological weapons, or creating designer children.
For a controversial technology to gain mainstream acceptance, it needs to be an answer to a major problem that everyone in society wants to see a solution found. Then after the ethical use of the technology has been accepted, it opens the door for its other uses.
Even if you want to ignore the ethical problems with the technology, the human genome is very complex and even with all out current knowledge we don't completely understand it. For example, our body's have safeguards built-in to the genetic systems that protect us against certain sicknesses and diseases. These systems are not perfect, but for the most part they work.
As a society we have achieved a lot of technological advancements in the last few decades and probably lots more to come in our future. Some of these advancement came at the cost of the environment, animals, and/or human lives.
By playing around with the human genome, we are playing with a very advance biological system which we don't totally understand. The human genome controls everything about how we are made. By turning on or off the wrong genes, we are potentially creating a life that could suffer a horrible fate in years or decades to come. We might not even be able to see the problems for several generations to come.
Unfortunately this is just the ways genetics work. So, like the nuclear genie that was released several decades ago when we exploded the first atomic bomb. Are we ready to release the genetic genie too?