Eugenics
Much of this concern is misplaced. Genetic counselling is not going to change the genetic composition of the human population to any noticeable extent. More relevant is the developing power to identify, and then to change directly, elements of the human genome (genetic engineering). This does have the potential to change the genetic structure of individual children. Long-term it has the potential to make more widespread changes to human populations. At the moment genetic engineering is limited to identifying defects in the foetus (unborn children) and eliminating the defect where possible or adapting the medical treatment for the benefit of the child.