Parents like to joke about the traits their kids may have picked up from them - whether it's musical or sporting ability and good looks. But sorry dad - it turns out that they inherit their brain power from their mums.

Multiple studies have shown that the X chromosome is responsible for carrying intelligence. Women have two of these chromosomes (XX) and men have only one (XY) - meaning they are twice as likely to pass down intelligence to their children than the fathers are.

One study at the Medical Research Council Social and Public Health Sciences Unit in Glasgow, revealed that kids' IQs tend to be similar to their mothers', the Mirror reports. Researchers interviewed kids every year from the age of 14-22.

They took into account various factors like education and socio-economic status and found that the best predictor of intelligence was their mothers. What's more, they found that that IQs of the young people were only around 15 points different.

However some experts believe the X chromosome does not tell the full story. Other studies say nurture and environment also have a role to play in developing a child's intelligence.

According to Psychology Spot it's estimated that 40-60 percent of intelligence is hereditary. The rest is thought to come from our environment, giving both parents an important role in emotional and intellectual development by building confidence, playing and teaching youngsters new skills.