Tory leader David Cameron has pledged to give faith schools the freedom to teach sex education “in a way that’s consistent with their beliefs.

In an interview with the Catholic Herald, he added that parents should be free to decide whether their children attended such classes.

Responding to a question about Labour’s Childrens, Schools and Families Bill, Mr Cameron said his party backed an amendment “to allow faith schools the freedom to teach these issues in line with their own values”.

Mr Cameron added: “I think parents who have chosen a faith-based education for their children should have that decision respected.

“I’m a big supporter of faith schools and I think it’s really important that their rights are protected in this way.”

Mr Cameron also told readers of the Herald that he favoured a reduction of the time limit for abortion, and opposed weakening current restrictions on euthanasia.

In the interview, Mr Cameron said: “My own view is that we do need to review the abortion limit. I think that the way medical science and technology have developed in the past few decades does mean that an upper limit of 20 or 22 weeks would be sensible.

“I’ll continue to support a modest reduction in the abortion limit. But what’s really important here is that Members of Parliament are always allowed a free vote on this issue.”

Mr Cameron also reiterated his opposition to assisted suicide. The Crown Prosecution Service recently published guidelines which meant that those helping people wanting to die were less likely to face charges.

The Conservative leader said: “My personal view is that if assisted dying is legalised, there is a danger that terminally ill people may feel pressurised into ending their lives if they feel they’ve become a burden on loved ones. I don’t believe anyone should be put in this position. So no, I don’t support any change in the law.”

Mr Cameron said that he did not favour overturning the controversial Human Embryology Act, which allows the creation of hybrid human and animal embryos. But he said that faith schools should be given freedom over how they taught sex education.

Mr Cameron’s outreach to religious and other traditional-minded voters is part of an overall message which stresses the importance of cultural factors and personal responsibility as a response to what the Conservatives have dubbed “Broken Britain”.

As part of this strategy, the Tory leader has repeatedly emphasised the importance of marriage, pledging to reduce taxes on married couples.

His comments come as the bid for religious voters intensifies. Earlier this year, a prominent Scottish Labour politician suggested that religious believers should vote for Labour.

Scottish Secretary Jim Murphy, in a speech to centre-left think tank Progress, said Labour was the natural party for religious voters to support.

In response, the leader of the Catholic Church in Scotland, Cardinal Keith O’Brien said that Labour had let religious voters down as regards legislation on embryo experimentation, abortion, civil partnerships and religious freedom.

Mr Cameron’s remarks will be seen as an attempt to reach out to religious voters. In an election expected to be extremely close, it is thought that such voters, although small in number, could prove crucial to the eventual outcome.