Doctors have been told they can help girls under 16 to obtain an abortion without involving the parents.
Young people have a right to confidentiality
However, new Department of Health guidance stresses every effort should be made to find adult support in this instance.
It also says a good rapport is key to providing under 16s with effective sexual health advice.
The guidance follows controversy over case of a 14-year-old girl allowed to have a secret abortion in May.
Michelle Smith, from Mansfield, Notts, decided to have an abortion after speaking to a community health worker at her school.
She took the first of two pills as part of the chemical abortion process, and although she later changed her mind when her mother found out what was happening, it was too late.
Anti-abortion campaigners have attacked the guidance as an "attack on parental responsibility".
The guidance has been sent to doctors and health professionals.
It is an update of guidance issued in 1986 after a ruling by the House of Lords enshrined the right of young people to confidential advice on contraception.
Family rights campaigner Victoria Gillick wanted to bar doctors from prescribing contraceptives to girls under 16 without telling the parents, but this was rejected.
The new guidance re-emphasises a young person's right to confidential sexual health guidance - and also makes explicit reference to abortion for the first time.
It says health workers should discuss:
- The emotional and physical implications of sexual activity, including the risks of pregnancy and sexually transmitted infections.
- Whether the relationship is mutually agreed or whether there may be coercion or abuse.
- The benefits of informing their GP and encouraging discussion with a parent or carer. Any refusal should be respected.
- In the case of abortion, where the young woman is competent to consent but cannot be persuaded to involve a parent, every effort should be made to help them find another adult to provide support, for example another family member of specialist youth worker.
- Any additional counselling or support needs.
Professor Jack Scarisbrick, of the anti-abortion group Life, said the guidance would lead to many more teenagers suffering in the way Michelle Smith had done.
He said: "Once again health professionals are being told that it is a young person¿s right to receive confidential contraceptive advice, even if they are under 16 and therefore breaking the law by having sex.
"We say under 16s should receive full protection from sexual experiences that they are emotionally and physically ill-equipped to deal with. They are, after all, children."
But Public Health Minister Melanie Johnson said: "Providing young people with clear support and advice about relationships and contraception is essential if we are to protect them, reduce the number of teenage pregnancies and tackle the spread of sexually transmitted infections.
"By updating this guidance we are ensuring that doctors, nurses and healthcare professionals are clear about providing young people with advice about sexual health and contraception and are providing the best possible care."
Dr Vivienne Nathanson, BMA Head of Science and Ethics welcomed the updated guidance.
She said: "This guidance usefully helps to clarify good practice for health care professionals and in turn also clarifies for competent young people that they can be secure, when seeking advice and treatment, that it will be in confidence.
"It is essential that competent young people's autonomy continues to be recognised and respected in this way, to ensure a good doctor-patient relationship, based on trust, within which young people feel they are able to seek advice."
Anne Weyman, chief executive of the Family Planning Association, said: "Young people worry a great deal about the confidentiality of health services, and it's one of the main reasons why they fail to seek professional advice.
"In the absence of other support, this leaves them vulnerable to unplanned pregnancy or sexually transmitted infections.
"All health professionals have a duty of confidentiality to their patients.
"It's vital services make this policy clear, so that young people feel confident enough to approach health professionals and receive the information and treatment they need."
Kathy French, Sexual Health Adviser, Royal College of Nursing said: "The biggest deterrents to under 16s seeking sexual health advice and using contraception have been addressed."