Parents should be told if under-age girls are given advice on contraception or abortion, to help them with "very serious" decisions, says a Tory MP.
Angela Watkinson said parents should be helped to protect children
Angela Watkinson is pushing for a change in the law, saying under-16s should have parental guidance before deciding to have an abortion.
About 4,000 under-16s a year have abortions in England and Wales.
But critics say confidentiality is essential, otherwise girls would be put off seeking the help they need.
Mrs Watkinson is arguing for a change in guidelines which currently guarantee confidentiality for under-16s as she presents her Contraception and Abortion (Parental Information) Bill to the Commons.
The Ten Minute Rule Bill is unlikely to become law, but Mrs Watkinson hopes it will publicise the issue more widely, and it may be voted on.
At a press conference on Tuesday, she said the whole premise of sex education was wrong.
"Very young children are bombarded with information about sex, information about contraception and then an assumption is made that they are going to make wise decisions with this information," she said.
She said this was "quite illogical", and said the decision to have an abortion was "far too serious... for a very young girl to reach on her own, or with the advice of a stranger".
Mrs Watkinson said many girls were "lulled into a false sense of security" by the emphasis on contraception - when in fact condoms often failed.
"I feel very strongly parents ought to be involved in these very serious life-changing decisions," she said.
But Liberal Democrat MP Evan Harris, a member of the British Medical Association's medical ethics committee, said the bill was "bad law, bad practice and bad ethics".
"The medical profession shares the government's view that a failure to respect confidentiality would deter girls from accessing the healthcare and advice that they need both in respect of abortion and contraception," Dr Harris said.
Parental information laws in the US are said to have resulted in a 15 to 20% drop in abortion rates for minors.
And Mrs Watkinson is backed by two experts who argue that scrapping confidential advice for the under-16s would not lead more to have unprotected sex.
Professor David Paton, of Nottingham University Business School, pointed to the UK's Gillick ruling of 1984, which banned the provision of contraceptives to under-16s without the parent's involvement but was overturned a year later.
Visits to family planning clinics had dropped during that year, but the number of pregnancies among under 16s had remained stable, he said - something partly explained by fewer minors choosing to have sex.
Putting aside the moral arguments, the evidence was "very clear" that the laws led to fewer abortions, pregnancies and possibly sexually transmitted diseases among teens, he said.
The government wants to halve the conception rate in under-18s in England by 2010.
But Dr Trevor Stammers, a GP and senior tutor at St George's, University of London, said he believed sexual health was "rapidly declining".
"We don't stand a snowball's chance of the teenage pregnancy targets being met," he said.
He said many doctors had been "conditioned" to act as providers of contraception, and some GPs were frightened of being sued if they did not provide the pill to minors.
And he said that the proposed bill was "the only way forward if we really do mean business about improving the sexual health of young people".
But Anne Weyman, chief executive of the FPA (formerly the Family Planning Association) said: "Compulsory parent notification of young people's sexual activity is detrimental because it deters young people from seeking the advice they need. "
She added: "Most young people will confide in their parents if they face an unplanned pregnancy .
"We also need to remember that the majority of young people (two thirds of boys and three quarters of girls) do not have sex under the age of 16."