Children get their intelligence from their mothers - sorry dads, but the evidence is looking conclusive.
Thanks to the work of Robert Lehrke, researchers have long thought that intelligence is carried on the X chromosome, and because women have two of them, they are more likely to pass on the intelligence levels.
And in studies using laboratory mice at the University of Cambridge, it was found that cognitive functions passed on from the father could be completely deactivated, meaning it is all down to mum.
This is based on the idea of 'conditioned genes' - genes with a biochemical tag - and some conditioned genes that come from the male, simply put, don't work.
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And, of course, some work the other way around.
So for example, the conditioned gene that passes on intelligence is from mum, and deactivated from dad, but the genes that carry sex, food and aggression is carried by paternal genes and deactivated in maternal genes.
Findings from the Medical Research Council Social and Public Health Sciences in Glasgow, also seem to confirm this theory.
In their study, 12,686 young people aged between 14 and 22 years were interviewed every year since 1994.
The researchers found that the best predictor of intelligence was the IQ of the mother after taking several factors into account, often a child's IQ was just 15 points difference to the mother.
But don't worry - dads can still make an impact on their little geniuses.
Intelligence is estimated to be around 40-60% hereditary (from those conditioned genes), the rest is all environmental.
So giving your child the best opportunities to flex their intellectual muscle is key to letting them fulfill their potential - but we didn't need science to tell us that.
