Mothers have always been good at passing on advice, but now it seems they are also likely to be the ones responsible for how intelligent their children are.
Recent scientific research suggests that rather than intelligence being genetically inherited from both their parents, it comes from their mother.
Writing a post for the Psychology Spot blog, American psychologist Jennifer Delgado states that studies have shown that intelligence genes originate from the X chromosome, of which women have two (men are made up of XY).
"At the basis of this idea are 'conditioned genes' that behave differently depending on their origin," she writes. "Some of these affected genes work only if they come from the mother. If that same gene is inherited from the father, it is deactivated."
As well studies from Germany and the University of Cambridge, Delgado points to a longitudinal study conducted by the Medical Research Council Social and Public Health Sciences Unit in Glasgow, Scotland.
"They interviewed every year since 1994, 12,686 young people aged between 14 and 22 years. The researchers took into account several factors, from the colour of the skin and education to socio-economic status.
"This way they found that the best predictor of intelligence was the IQ of the mother.
"In fact, the ratio of young people's intelligence varied only an average of 15 points from that of their mothers."
Fortunately Dads, all this evidence doesn't suggest that paternal genes don't have any effect on intelligence. Other studies have shown that a father's genes accumulate in the limbic system of the brain, which is responsible for mood and instinct, and controls basic functions like sex, hunger and aggression.
In contrast, the mother's cells are in the cerebral cortex, where cognitive functions reside like memory, thought, perception and language.
- Stuff