Effects of inbreeding and how its widespread practice among Muslims creates Muslim offspring with increased frequency of genetic diseases?
Result of Inbreeding in the Animal World
The 12 February, 2012 edition of the Statesman, a Calcutta based daily, carried an article “A question of relationship” by Maneka Gandhi, the well-known activist fighting for animal welfare.  At the very outset, Ms Gandhi says,
“Inbreeding is taboo in most cultures and for good reason. Unfortunately, man discovered artificial insemination and has created a Pandora’s Box of disease and suffering in the animal kingdom. … More and more pedigreed animals continue to pour into my hospital with the same type of diseases. When we check, we find that several dogs suffering from the same disease – like hip dysplasia – have come from the same breeder. I have him raided. We find three females, all pregnant by their brother. Inbreeding or incest is defined as the use of close relations for breeding, such as mother to son, father to daughter, brother to sister. It is taboo in most cultures and for good reason. Genes carry the map of who you will be and what diseases you will suffer from.”
To make her point, she continues,
“Let us suppose you carry the “bad” gene of a disease. You mate with someone who does not have the disease. Bad genes are usually recessive — which means they are weaker than good genes. So when the bad gene is mixed with a good gene it has less than a 50 per cent chance of affecting your child. But if you were to mate with your brother, your child would have a much stronger bad gene as both of you are carrying it. Which communities have the most physical problems? Well, those small sects and clans that marry first cousins. One group that has been intensively studied is the Ashkenazim, or Eastern-European Jews, in whom exists a large number of genetic diseases, especially of a neurological nature.”
A cheetah cub physically
deformed due to inbreeding
Then she cites an example and says that the researchers in Finland could have identified 39 genetic diseases, affecting human beings, unique to that country and these are known as the Finnish Disease Heritage. These diseases most commonly affect the eyes and the nervous system of the victims. The researchers could also discover that a close relationship between parents increases the risk of miscarriage, stillbirth and early death of children as a result of weakened immunity against disease. The same thing applies to animals.
The Damage done by the Animal Breeders
As a matter of fact, Inbred animals lose their ability to produce antibodies and hence to fight diseases. Suddenly whole species can be lost to infections that would have little effect on a normal animal. “Scientists have produced laboratory animals, strains of mice, rats and other animals that are so inbred as to be genetically identical. Each animal in one of these strains is the identical twin (aside from sex) of every other animal of that strain. These animals must be kept in a nearly sterile environment because their immune systems are not capable of fighting off any diseases”, she adds.
If the population of a certain animal declines, inbreeding becomes very common and the pups become vulnerable to various diseases due to genetic disorder. For example, the cheetah population has been drastically reduced due to habitat restriction and over-hunting to a very small number of individuals. As a result, all cheetahs now come from a very small gene pool and hence a virus can take them to extinction as they have no resistance. “and currently they are being decimated by feline infectious peritonitis, which has a disease rate in domestic cats that ranges from one to five per cent but 50-60 per cent in cheetahs”, says Ms Gandhi.
Asiatic lions in Gir Forest, Gujarat, India, are facing the same problem. As their population has declined to a few hundred strong and there is no mechanism for preventing inbreeding. “In the prides, most lionesses are related to one another. The alpha males of two neighbouring prides can be from the same litter; one brother may come to acquire leadership over another’s pride, and subsequently mate with his “nieces” or cousins.” In a similar manner, Wolf packs and Giant Pandas suffer from the same effects of inbreeding which has led to poor fertility and high infant mortality. “As panda populations become more isolated from one another (due to humans blocking the routes that pandas once used to move from one area to another), they have greater difficulty in finding a mate with different genes.”
A White tiger cub physically deformed
due to inbreeding
In the animal kingdom, animals have their own live pattern for avoiding inbreeding. For example, animals like lions, monkeys and dogs kick young males out of the herd to prevent them from mating with female relatives. Even fruit flies have a sensing mechanism to avoid too close inbreeding. But the invention of artificial insemination by man has destroyed all such natural barricades to check inbreeding. And at the same time, has opened the door for several kinds of diseases, so far unknown, to the sufferings in the animal kingdom. But the animal breeders pay little heed to these sufferings and proceed with their own set of goals such as to make the animal bigger, fatter or smaller, one that gives more milk, more meat and so on. By the use of this controlled breeding, they have been able to produce chickens that would produce more eggs or more meat. This they do for all animals — dogs, cats, cows, pigs, geese and practically all the animals that are used by man have been tampered with in this way.
“The result is much weakened species with a host of diseases and that is the reason why nearly 60 per cent of the world’s antibiotics are now fed to animals. But the most obvious effects of inbreeding are poorer reproductive efficiency including higher mortality rates, lower growth rates and a higher frequency of hereditary abnormalities. This has been shown by numerous studies with cattle, horses, sheep, swine and laboratory animals. The greater the degree of inbreeding, the greater is the reduction in performance”, laments Ms Gandhi. Among the domestic animals, most of these experiments were carried out with cows, cats and dogs. These breeders are motivated by short-term profit rather than the health and well being of the animals. To learn more, reader may see 
Incest in man
The incest taboo is and has been one of the most common of all cultural taboos, both in current nations and many past societies, with legal penalties imposed in some jurisdictions. Though consensual adult incest is seen by some as a victimless crime and is illegal or partially prohibited in most countries of the civilized world, in France, Turkey, Israel and the Ivory Coast have no legal prohibitions on consensual incest between adults. In Switzerland, this going to be a legalized institution. It would be relevant to mention here that, in some societies, such as that of Ancient Egypt, brother–sister, father–daughter, and mother–son relations were practiced among royalty as a means of perpetuating the royal lineage.
Genetic disorder in lions of the Gir Forest, due to inbreeding
In ancient China, first cousins with the same surnames (i.e., those born to the father's brothers) were not permitted to marry. But those with different surnames (i.e., maternal cousins and paternal cousins born to the father's sisters) were permitted to marry. In ancient Greece, the story of Oedipus, with a theme of inadvertent incest between a mother and son, ends in disaster. This shows that ancient taboos against incest as Oedipus is punished for incestuous actions by blinding himself. In the "sequel" to Oedipus, Antigone, his four children are also punished for their parents having been incestuous. But Greek law allowed marriage between a brother and sister if they had different mothers.
Incest results in close inbreeding, i.e. reproduction between two individuals with a common ancestor. According to the biologists, inbreeding leads to a higher probability of congenital birth defects and death in infancy, because it increases that proportion of zygotes that are homozygous, in particular for deleterious recessive alleles that produce such disorders. 
In Islam and Biblical religions, incestuous marriage lies as a foundation stone. Both the Bible and the Koran believe that the human race started its journey from a single pair of man and woman, and hence marriage between brothers and sisters in the next generation was unavoidable. In fact, in the very beginning of the Bible, one finds two sons of Adam and Eve, namely Cain and Abel, lust for their only sister, and ultimately Cain murders his younger brother to marry her. Besides that, these two holy books provide many instances of inbreeding or incestuous marriage. The Lot of the Bible, identified as a prophet, Prophet Lut, in the Koran, slept with his two daughters and impregnated them. Nahor, the younger brother of Prophet Abraham, is seen to marry Milcah, the daughter of his younger brother Haran (Genesis: 11/29-30). The holy Bible also says, “Do not dishonor your father by having sexual relation with your mother” and “Do not have sexual relation with your father’s wives; that would dishonor your father” (Leviticus 18/ 7,8). So, according to the Bible, a man can have sexual relation with his mother and other wives of his father, if his father goes absconding or dies.
Incest in Muslim community
Regarding the women, whom a Muslim male can marry, the Koran says,
"you shall not marry the women whom your fathers married: all previous such marriages excepted. That was an evil practice, indecent and abominable… You are forbidden to marry your mothers, your daughters, your sisters, your paternal and maternal aunts, the daughters of your brothers and sisters, your foster-mothers, your foster-sisters, the mothers of your wives, your step-daughters who are in your charge, born of the wives with whom you have lain (it is no offence for you to marry your step-daughters if you have not consummated your marriage with their mothers), and the wives of your own begotten sons. You are also forbidden to take in marriage two sisters at one and the same time: all previous such marriages excepted. Surely Allah is forgiving and merciful." (Q 4:22-23)
"All women other than these are lawful for you provided you court them with your wealth in modest conduct, not in fornication. Give them their dowry for the enjoyment you have had of them as a duty. Surely Allah is all-knowing and wise" (Q 4:24).
So, it appears from the above verses of the Koran that, except a few very near relations, one can marry every other woman and in some particular cases Koran permits one to marry his step-daughters. Moreover, it becomes evident from the phrase "all previous such marriages excepted" that the nearest kin whom the Koran declares forbidden, were lawful in pre-Islamic Arabian society.
From the above revelations, it becomes evident that Allah allows Muslims to marry very close relations, like first cousins and nieces. In some cases, Islam allows a man to marry his own daughter, perhaps following the legacy of Prophet Lut. 
In fact, inbreeding rates are found to be more than 50% in many Islamic countries. As a result, these Islamic countries have two times more handicapped children with genetic defects than in non-Muslim countries. While Islam encourages inbreeding, it is certainly wrong from a biological and genetic viewpoint, because higher variability is preferable. In Arab countries there are so many people suffering from sickle cell anemia, thalassemia, diabetes, hydrocephalus and many more ailments. The sense of sexual reproduction is to achieve higher variability, Islamic habits, on the contrary, are working against it, against nature, against evolution, in favour of stagnation and corruption. 
(To be continued)