In order to be considered mentally retarded, you must have an IQ below 75, have significant limitations in two or more adaptive skill areas, and the condition is present from childhood (defined as age 18 or younger). People can be mentally retarded as all different levels. About 78% of mentally retarded people will only be a little slower than the average person, while in others it is very apparent (Arc of New Jersey). There are many causes of mental retardation.
             One cause of mental retardation is of genetic conditions. That includes; abnormal gene mixes from parents, errors when genes combine, overexposure to x-rays, and many more reasons. More than 500 genetic diseases are associated with mental retardation. Down Syndrome is an example of a chromosomal disorder (Mental Retardation Issues). Chromosomal disorders occur every once in a while, and are caused by too many or too few chromosomes in the restructure of the chromosomes (The Arc of New Jersey).
             Another cause is problems during pregnancy. It could happen if the mother drinks or does drugs while pregnant with the baby. Other risks include malnutrition, certain environmental contaminants, and the mother could get ill during the pregnancy. Pregnant women who are infected with HIV may pass it on to their child. Also very stressful and physical pregnancies and births can cause damage to a child’s brain (Introduction to Mental Retardation).
             Mental Retardation also occurs frequently after birth. Childhood diseases such as big coughs, chicken pox, measles, and hip disease, which may lead to meningitis and encephalitis, can damage the brain, as can accidents such as being hit in the head, near drowning situations, and most other accidents involving the head. Another that can be harmful to a child mentally is environmental fumes, lead, mercury, and other dangerous toxins (Introduction to An American
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