A6-year-old child with a mental age of 6 would have an iq of

The IQ reflects the relationship between a childs metal age (MA) and his or her actual or chronological age(CA). One way of determining the IQ of the child is to use the mathematical expression derived by Wilhelm Stern. Stating that,

IQ=MA x 100/CA

where MA is the Mental Age and CA is the chronological age.

Thus, the IQ for a child having a Mental Age of 6 and a chronological age is 6,

IQ=6 x100/6 =100

Thus the IQ of the child is 100.

"1. it should be, it has been for about 20 years, and it's really not much different in the end than breeding animals to have particular traits. there are always concerns about genetically engineered animals/plants affecting the environment in unexpected negative ways, but i can't think of an example where the fears didn't turn out to be baseless.  

first, as you point out, it would be a great advance in pharmacology, to be able to tailor drugs and their doses to me. the pros involve better medical treatment. the cons involve privacy issues like insurance companies denying coverage to people with genetic risk factors. looking at dna markers wouldn't affect the frequency of genetic diseases, but it would allow detection of them earlier. and ok, actually i suppose that if people used this information to avoid having children with genetic diseases, some might decrease in frequency."