Twins studies show identical twin correlations of .7-.8,
fraternal of .3-.4 which means high levels of environmental deprivations may
swam out effects of genes. In other words, if two twins in
an identical pair incline to have closer IQ's than
two twins in a fraternal pair, then genetic factor perhaps
play a role in IQ. And the correlation between the identical closer.
Therefore, identical twins are certainly more possible to have
the similar IQ than are fraternal twins.
