Scientists from the University of Nijmegen in the Netherlands found that certain genetic abnormalities in the chromosomes of a person connected with intellectual disabilities its progeny, and the greater the chance for them to appear, the older the father of the child. Genetic disorders are associated with variations in the number of copies of genes, among which are repeated inverted or irrelevant DNA sequence.
While it has long been known that the probability of birth defects such as down syndrome increases with the age of the mother, age of father was also an important factor.
Scientists have studied the type of genetic mutations in children with an IQ less than 70, it turned out that the father were more often the source of these gene mutations than the mother. Approximately 70 percent of cases of duplications and deletions of DNA responsible for the violation of the intellect, were inherited from the fathers.
The key to mutations became paternal age, the older was a man compared to fathers of children without mental problems, the higher was the risk of mutation.