Increasing the age of compulsory education and training to 18 could help to cut England's persistently high teenage pregnancy rates, new research suggests.
Studies show that other countries which have raised their school- leaving ages have seen a reduction in the number of teenage girls becoming pregnant.
Researchers looked at rises in the participation age in Norway and the United States. Attitudes to teenage mothers vary considerably between the countries, but the impact of increasing the duration of education was similar, especially among lower-achieving pupils.
"Findings suggest that policy interventions to increase female education at the lower tail of educational distribution may be an effective means of reducing rates of teenage childbearing," says the research in The Economic Journal, which is published by the Royal Economic Society.
Academics identified two reasons for the drop in teenage pregnancy rates. The first was what they called the "incarceration effect", which meant young women did not have the desire, time or opportunity to engage in "risky behaviour".
Raising levels of education also deterred teenagers from having children because they would have to give up higher earning potential.
"We call the fact that additional schooling may make you `smarter', and hence decide to postpone childbearing, `the current human capital effect'," said the researchers, led by Sandra E Black, associate professor of economics at the University of California, Los Angeles.
The research analysed census data from the two countries from 1940 to 1980, when compulsory schooling was raised from 14 to 16 in Norway and 16 to 18 in the US.
In America, the probability of teen births fell by almost 9 per cent after the changes; in Norway, it fell by 3.5 per cent. In both countries, the impact was bigger in urban than rural areas.
Since the 1970s, the teenage pregnancy rate in Norway, which has a more supportive attitude to teenage mothers, has fallen substantially below that in the US.
Young people in England will have to remain in education or training until the age of 18 by 2015.
The latest figures on teen pregnancy in England and Wales show under-18 conception rates fell by 13 per cent between 1998 and 2006.
But while rates are at their lowest for 20 years, they still fall far short of a government target to cut teen pregnancies by 50 per cent by 2010.
A spokeswoman for the Teenage Pregnancy Independent Advisory Group, which advises ministers, said: "Raising the participation age could be extremely helpful in protecting young people from teenage pregnancy. But we are adamant that we need to have excellent sex and relationship education in schools.
"This has to be the major factor, and it has to be extended so that it also goes right through to 18."
The group also called for schools to offer on-site health services, including contraception and advice.