Many people are put off Christianity by its apparent obsession with policing other people's sex lives.

As often happens, moral attitudes in society change more quickly than the views of church leaders. The church then comes to seem old-fashioned. Many people can remember, before the debate about same-sex partnerships, equally intense debates about whether Christians should permit the remarriage of divorcees or the use of contraception.

Negative attitutes to sexuality have been known among Christians since the earliest days. The first indication is Paul's remark in 1 Corinthians 7:1 'Now concerning the matters about which you wrote: it is well for a man not to touch a woman.' As the original manuscripts do not contain punctuation marks, we cannot be sure that the second half of the sentence is Paul's quotation of what the Corinthian Christians believed, rather than his own belief; but in either case it provides evidence of a negative attitude to all sexual activity. The New Testament texts which mention same-sex activity only do so in lists of sins to be avoided;  it is not picked out as specially wicked.

By the fourth century the tradition had developed of believing all sexual activity immoral, so Jerome could declare that 'Marriage populates the world; virginity populates heaven'. Throughout the Middle Ages the dominant view was that monks and nuns, by being celibate, were better Christians than the married. Although gay sex was forbidden church leaders paid far more attention to married couples, forbidding all sex acts designed to avoid pregnancy or performed on Wednesdays, Fridays and other special days.

One of the distinctive events of the Reformation was Luther's encouraging monks and nuns to abandon their vows of celibacy and marry. The strongest argument in Luther's favour was that if everyone was celibate there would be no children. This argument set the scene for subsequent arguments that sexual activity was only justified for procreation.

During the twentieth century church leaders slowly accepted a more positive attitude to sexuality, whether or not children were wanted. However the Roman Catholic Church forbade the use of contraception in the 1967 Encyclical Humanae Vitae,  and that remains its official position today. Around the same time most Protestants came to accept it as morally permissible.

Throughout most of its history Christianity has put a lot of effort into debating sexual ethics. However, before the last 20 years same-sex activity has never been treated as an important issue, let alone serious enough to cause schism.