Another factor of determining intelligence in children is the education of the parents.  In the study conducted by Guang Guo and Elizabeth Stearns, the results show that for children whose mothers have less than a high school education, heritability accounts for only about 4% of the variance in intellectual development compared with 68% for those whose mothers are high school graduates.  This means that the higher the education of the mother, the less involvement the environment is going to play in the transfer of intelligence.