Many parents are very much concern about their blood group combination. A common query is ‘which combination of blood group between husband and wife is better?’ If the husband’s and wife’s blood group is same (for example husband is ‘A’ and wife is ‘A’) there is no problem. But if the wife is having negative blood group (for example ‘A negative’) and the husband is positive (A positive), a ‘Lethal Gene’ is formed which further prevent the successful development of the embryo. In that case baby may born dead or may be blind since birth. Besides these, when a negative mother carries a positive baby, the first baby remains unaffected. But during delivery positive blood from baby enters the mother through placenta (গর্ভফুল).This produce an antibody in mother’s blood which is called ‘Rh antibody’. During second pregnancy if the baby is again positive the mother’s preformed antibody enters the baby through placenta and destroy baby’s red blood cell. This is known as ‘Rh Incompatibility’. If husband is positive baby should have its blood group checked immediate after birth. If baby is positive mother should be given ‘anti D’ injection within 72 hrs of delivery. If baby is negative nothing to do.