Children of older fathers may have less 'brain power'

Researchers think that this may be caused by mutations that accumulate in older men's sperm. The study comes from the University of Queensland, where a team looked at data from 33 437 children born between 1959 and 1965 in the US. Each child was tested for a range of cognitive functions at the age of eight months, four years and seven years.

The study was adjusted for socio-economic factors such as family income and the education level of the father.

They found that the older the father the more likely the child was to have lower scores on the various tests. Interestingly, the older the mother, the higher the children scored on the cognitive tests. This latter finding ties in with previous studies that have found that older women have brighter children, possibly because of a more nurturing home environment.

However, researchers said that socio-economic factors may play a part, as well as genetics, although they would expect a child to benefit from having an older father who would generally be more economically stable.

In the developed world, there is a general trend towards older parenting.