The Local Government Association (LGA) is calling for schools to teach all children about sex education unless their parents can show they are able to give their children appropriate information elsewhere.

Currently, parents can withdraw their children from sex education lessons.

An LGA spokeswoman said: "Ignorance is one of the key factors why teenage girls become pregnant."

The call came as the LGA and the Association of Directors of Social Services began their annual social services conference in Torquay on Wednesday.

It is the LGA's response to a report by the government's social exclusion unit which called for teenage pregnancies to be halved in 10 years, but rejected demands for compulsory sex education classes.

The LGA call comes after an earlier call by the Royal College of Nursing's conference for all school nurses at secondary schools to be allowed to prescribe contraceptives.

Britain has the highest teenage pregnancy rate in Europe and social workers and health staff say practical steps must be taken to reduce this.

Medical experts also say rates of sexually transmitted diseases are rising fast among the young.

Opponents

But anti-abortion and pro-family groups are against making sex education in schools compulsory.

The group Family and Youth Concern believes sex education encourages young people to experiment with sex.

It wants to see schools emphasising the need for young girls to say no to sex.

Its views are supported by Ann Widdecombe, deputy leader of the Conservatives.

And a doctor at a London teaching hospital recently backed the abstinence line in an editorial in the Postgraduate Medical Journal.

Dr Trevor Stammers, a London GP and tutor in general practice at St George's Hospital, said providing sex education and contraceptives did not deal with the causes of teenage pregnancy which included low self-esteem among young women.

However, organisations like the British Pregnancy Advisory Service (BPAS) say preaching abstinence ignores the reality in which young people now live.

The BPAS sees 10,000 teenagers a year who are seeking abortions. Around 1,000 are under 16.

"The more access there is to family planning, the less unwanted pregnancies there will be," its says.