Because of their blood relation, marrying a close relative is prohibited because chances of abnormal offspring is too high – a myth or a fact?
A Christian friend said that this is being practiced before the book of Numbers in the New Testament but later becomes prohibited. One Muslim friend told me that marrying a cousin is not wrong because the abnormalities of the child is not due to union of relatives but his parents have the same blood type. In their religion they can marry relatives provided they do not have the same blood type.
Marrying someone in the family has its own merits, advantages and disadvantages like diseases of the blood can be inherited. Since the blood flows to different parts of the body, diseases like syphilis, diabetes, leukemia, anemia, etc could leave traces within the veins, arteries and capillaries.
Generally although blood types are inherited, experts said that they have nothing to do with the child’s abnormality; though it is also true that there are blood types that are not compatible with each other but this is only applicable in cases of transfusion.
For people thinking of marrying their cousins – what you should worry about is the so called RH factor, a group of blood type which usually cause trouble to married couples who are first degree relatives.
This particular type of blood was name after the monkey named Rhesus where it was first studied and is usually present among Orientals and whites. Study shows that about 85 percent of humans carry the RH factor and these called RH positive. The remaining 15 percent who do not have such RH factor are called RH negative.
If an RH positive man marries an RH negative woman, big chances that their child will develop a serious condition known as erythroblastosis, which is characterized by anemia, swelling of the body and jaundice. Worst scenario is the child may die. This disease is actually rare and usually happened in the second or third child. Recent studies show that only one of 26 children born of parents with incompatible blood will most likely develop this condition. A blood test for the RH factor will save you a lot from worries and anxieties.
However, being healthy parents is not an assurance that your child will also be healthy. There are records that show a child’s parents carry a defective gene which could crop up late within the member of the family. Dr. Victor McKusick, geneticist and professor of medicine at John Hopkins School of Medicine confirmed this fact and even went further in saying that human beings carry an average of three defective recessive genes which may pass on to their children. The probability that these bad genes to appear is increased if the family has a record of hereditary diseases; otherwise – a normal healthy couple could give birth to a normal and healthy child, Dr. McKusick said.
Marrying someone within the family with history of hereditary disease is risky, chances that these bad elements would appear and manifest later in life to the child. Limiting the gene flow through inbreeding can lead to still-births, higher sterility rates or congenital malformations study shows.
“The physical and mental qualities of offspring coming from first cousins or other near relatives are subject to the same laws of heredity which govern children of non-relatives. If the father and the mother are closely related, the chances of the child’s inheriting the traits appearing in that family are very much increased. If these characteristics happened to be good, so much the better for the child; but if there happens to exist some physical or mental deficiency in the family, the child will be more likely to inherit the undesirable traits. Marriages between relatives, therefore, should be considered individually. In general, perhaps, such marriages, should not be encouraged, but neither should they be prohibited,” an advice on inbreeding offered by Dr. Hannah and Abraham Stone in their book A Marriage Manual.