Inherited defects causes a higher number of different birth defect. In fact, 60 percent is found from pollutions and others causes but 20 percent is divided equally between single-gene disorders, chromosomal syndromes and teratogenic causes.(Polzin 2005) Single- gene disorder means when one parents genes are dominant and the other parent has a recessive gene, which means that the unborn infant would get the genes from the parent that has the dominant gene. In some cases when both parents have recessive