I've read several articles recently about people who believe that scientists should not "play God" when it comes to genetic engineering. This seems to include the act of creating new kinds of life that don't currently exist on Earth, which in turn raises some interesting philosophical questions.
For example, let's say that scientists come up with a way to artificially boost an immune system using a new kind of genetically engineered cell. A person with such an immune system would be a new kind of life form in the sense that they'd contain genes in their DNA that were designed by other humans. Would they still be considered human? If so, what is the criteria for determining what genetic modifications keep you human and which do not?
Similarly, let's say that a way to boost intelligence by 50% is invented that works by adding a new region to the brain. Would people with this enhancement still be considered human?
Any one particular enhancement in isolation might seem like a minor improvement, but when you add up the combined effect of hundreds of enhancements, the end result would be to humans as humans are to apes.
I think the debate about scientists "playing God" is interesting but ultimately academic, because history shows that most people are very eager to improve their competitiveness through the application of technology. The popularity of plastic surgery is just one example of this.
If parents are willing to spend large amounts of time and money to give their children a competitive edge, how many do you think wouldn't want their children to be born 50% smarter than everyone else? And even if some countries outlaw such enhancements, you can bet that other countries would allow them since it would give their country a competitive edge. Would it be possible to enforce a world-wide ban on such practices? I doubt it, especially since humanity will at the same time be colonizing nearby planets which will make tracking and enforcement increasingly difficult.
Although a small subset of the population will shun the benefits of radical genetic breakthroughs, my hunch is that the bulk of the population will embrace them and hence accelerate our evolution toward a new, post-human life form.