This topic has been started largely for AIJ who wants to discuss the subject.
My involvement throughout my career has been to run occasional prenatal diagnostic tests for genetic disease. As a geneticist, I, along with all my colleagues throughout N. America support freedom of choice. Our role is to support the choices that patients make. So if a couple decide to keep a foetus diagnosed with Down's syndrome it is our responsibility to support that choice and to arrange for the best supportive care to maximize that child's potential. Should they make the other choice then our role is to support that choice and provide supportive care for the couple.