The baby simulators form part of sex education classes across the world and are touted as a key weapon to discourage girls from having sex.

But a new study of the programme in Australia, published in The Lancet, found girls who took part were twice as likely to get pregnant and a third more likely to have an abortion than those who did not.

Researchers suggested the dolls, which cost around £1,000 each, do not prevent underage sex and unwanted pregnancies.