What are designer babies? Designer babies are what will come to pass in the next 10 to 20 years. That is to say, that we will be able to pick our child's eye color, hair color, or whether our hair glows in the dark or not, and most importantly rid our children of congenital diseases or disorders.
In the grand scheme of things, this is a convergence of the human race. As we will all trend to pick lots of the same fundamental traits. For example, everybody wants their children to be smarter, more beautiful, not prone to weight gain, depression, etc... These designer babies will make people very alike to one another.
Is this a good idea? Overall, I'd say yes. However, it does introduce certain frailties into the gene pool. One of the advantages of our sexual reproduction is that it introduces diversity into the system. Different ways of doing things, different ways of thinking about things, different immune systems etc. A lot of that will be lost with designer babies. Perhaps this won't matter, given that computers will do most of the thinking for us and that we won't be prone to any diseases at all. However, I do believe that a part of us, human beings, will be lost in this transformation. For all our short-comings and all our frailties, there is a underlying beauty of it all. But alas, it cannot be stopped. It is like the wind, fighting it would be a futile endeavor.