Human Birth Defects and Genetics
Birth defects are structural abnormalities that develop as a fetus grows in the womb. They often have complex or unknown causes. In particular, genetics can interact with other conditions, including environmental factors, to cause some human birth defects. Genetic Transmission Genes determine many aspects of physical development. As a rule, one copy of each gene is inherited from each parent. Several types of inheritance are associated with transmission of genetic information. Some traits follow dominant inheritance; only one copy of the gene is necessary to experience a condition, and it overrides the other copy. Others follow recessive inheritance; two copies of the gene are needed in order for its effects to manifest, and individuals with a single copy are unaffected. Other genes follow more complex patterns of inheritance. This is likely the way birth defects are affected by genetics; the extent of the effect of genetics and the exact methods of transmission are not fully u...