Consanguineous marriage is marriage between persons having blood relation. Mostly the baby born out of such marital relation leads to deformity of the child and most commonly mentally retarded. Everyone of us have genes which are segments of varying lengths of a molecule called DNA. Each and every structure and function of the body is under the control of a pair of genes in most cases. Each human body cell carries nearly 50 to 100,000 of these genes, as pairs, usually a pair for each characteristic. Out of these about 4 to 8 are unwanted and faulty but as they are weak or recessive do not reveal the defect. The reason being that the other member of the pair is normal and powerful or dominant and thus suppresses the injurious effects of the faulty one. For any of those 4 - 8 genes to have an impact, they need to be in identical pairs, which means that each parent has to contribute one member of the pair. Thus the child being born out of baby born out of such marital relation leads to deformity of the child.
