Fetus, Genetics, Uterus, Morphogenesis, Chromosome, Pregnancy, Postnatal, Teratology, Genetic disorder, Congenital abnormality  Congenital disorder involves defects in or damage to a developing fetus. It may be the result of genetic abnormalities, the intrauterine environment, errors of morphogenesis, or a chromosomal abnormality. The outcome of the disorder will further depend on complex interactions between the pre-natal deficit and the post-natal environment. Congenital disorders vary widely in causation and abnormalities. Any substance that causes birth defects is known as a teratogen. The older term congenital disorder does not necessarily refer to a genetic disorder despite the similarity of the words.