Compulsory sex and relationships lessons for 11-year-old children are to include classroom discussions on gay unions and civil partnerships. Secondary pupils will learn about contraception and sexually transmitted infections (STIs), while primary school children will learn about their bodies and friendships, a review of sex education has concluded.

The review was ordered in October after ministers announced that sex and relationships education (SRE) lessons should be made compulsory to help primary and secondary pupils to “navigate the complexities of modern life” and to ensure that children learnt their sex education from the classroom, not the playground.

The changes to personal, social, health and economic education (PSHE) classes mark the culmination of decades of campaigning by sexual health organisations, who believe that the patchy nature of sex education in schools is helping to fuel a record level of teenage pregnancy and STIs in England.

Last night campaigners welcomed the review, conducted by Sir Alasdair MacDonald, a secondary head teacher in Tower Hamlets, East London. However, they suggested that its recommendations did not go far enough.

Although the new PSHE classes will be compulsory from 2011, faith schools in England will be given licence to provide sex and relationships education within the context of their own values. This could mean that children will be taught that their religion regards the use of contraceptives as a sin. Parents will also have a legal right to withdraw children from SRE classes. Currently one in 2,500 parents withdraws children from nonstatutory sex education classes.

Sexual health charities warned that allowing parents to opt out, even if it involved only a small number, was an infringement of young people’s rights. Julie Bentley, chief executive of fpa, formerly the Family Planning Association, said that while religion and sex education were not incompatible, schools should not be allowed to interpret the report “to mean they can tell young people, for example, that contraception isn’t a matter of choice – it is simply wrong”.

She added: “We would like further assurances that when SRE becomes statutory, all schools will teach it responsibly, ethically and factually as a core subject.”

Simon Blake, national director of the sexual health charity Brook, said: “Young people need to understand the law – that you can get contraception, that you can have an abortion – and understand the health benefits of practising safer sex. It would not be right for anyone to tell them that this is wrong, but it is OK for them to be told that some people believe it is wrong.”

The Catholic Education Service for England and Wales welcomed the opt-out. “This is a crucial right in a community where parents are the first educators of their children, because parents are responsible for bringing up their children, and not the State,” it said.

Ed Balls, the Schools Secretary, accepted Sir Alasdair’s review, subject to a four-month consultation that will look again at the content of SRE lessons, but told MPs that he would keep the right of nonacceptance under review.

Sir Alasdair said that making PSHE compulsory would help the quality of teaching. “There is probably greater variability in teaching and learning in this subject than in most other subjects,” he said.

Times recommends

• Students to rate lecturers online
• Students face big rise in university fees
• Queen’s English Society boss’s poor spelling