Designer babies are babies whose genetic makeup has been chosen by the parents. They do this by taking eggs from the mother and sperm from the father, and then they use a special process called in-vitro fertilization to mix the eggs and sperm together. They then can look at the genetic material in each egg and sperm, and choose which ones they want to use to make the baby. They can choose eggs and sperm that will make the baby have certain physical characteristics, like eye color or hair color, or that will make the baby more likely to not get certain diseases.