Yes, it is done in a variety of ways. One way is to do a genetic history of the parents to determine if there is a predisposition for a genetic disorder(taysachs, Muscular dystrophy, cancer, Huntington's disease). Prevention then becomes the choice to not have a child. Another way to prevent certain disorders is for proper pre-natal care. Certain disorders arise during pregnancy and can be caused by exposure to environmental factors (cigarette smoke, alcohol) or a lack of proper diet or vitamins. This lack of proper pre-natal care caused mutations to occur during development and thus 'causing' certain genes to mutate and create genetic disorders that can either be fatal (miscarriage), a life-long challenge (down's syndrome) or minimal (brown staining of baby teeth). Certain genetic disorders can be diagnosed before delivery and corrected while the fetus is still in the womb, such as heart defects, or can be corrected after birth. One last way to prevent genetic disorders can be determined by the age at which a woman becomes pregnant. Older women, over 35 years old, have a much high rate of Down's syndrome than those women who are younger. Women are born with all their eggs and as they age, so do their eggs. Lastly, is not currently readily available and that is genetic therapy where locations of mutated genes are targets before they do harm and are 'fixed'.