A congenital disorder, also known as birth defect, is a condition existing at or before birth regardless of cause. Of these disorders, those characterized by structural deformities are termed “congenital anomalies” and involve defects in a developing fetus. Birth defects vary widely in cause and symptoms. Any substance that causes birth defects is known as a teratogen. Some disorders can be detected before birth through prenatal diagnosis (prophecy).
Birth defects may be the result of genetic or environmental factors. This includes errors of morphogenesis, infection, epigenetic modifications on a parental germline, or a chromosomal abnormality. The outcome of the disorder will depend on complex interactions between the pre-natal deficit and the post-natal environment
Animal studies indicate that the mother’s (and likely the father’s) diet, vitamin intake, and glucose levels prior to ovulation and conception have long-term effects on fetal growth and adolescent and adult disease. Animal studies have shown that paternal exposures prior to conception and during pregnancy result in increased risk of certain birth defects and cancers. This research suggests that paternal food deprivation, germ line mutations, alcohol use, chemical mutagens, age, smoking habits and epigenetic alterations can affect birth outcomes.However, the relationship between offspring health and paternal exposures, age, and lifestyle are still relatively weak. This is likely because paternal exposures and their effects on the fetus are studied far less extensively than maternal exposures.