This means short mothers and fathers are not dooming their offspring to a vertically-challenged life.

"Mid-parental height", or the average of both parent's heights, is used to predict how tall a child will be.

Health workers use the calculation to work out whether children are thriving or not.

'Misleading'

But its reliability has been called into question by researchers from the Department of Child Health at the University of Newcastle.

Their survey of more than 3,400 children found that while the system worked reasonably well for children whose parents were of average height, when applied to more extreme cases, the system was "misleading".

In fact, children of very tall parents were quite likely to be shorter than the average worked out for them, and children of extremely short parents likely to prove slightly taller.

This is a principle known as "regression to the mean", well-known in biology and statistics.

Malnutrition

Children's heights often give a clue to any underlying health problem they may have.

If a child is too short, it may be due to serious underlying disease, malnutrition or even abuse, so it is important that doctors correctly identify the cause.

The researchers noted: "We suggest that few paediatricians are aware of the need to allow for regression and these data demonstrate that doing so might substantially alter their interpretation of a child's growth pattern."