There are many factors that unite people, and there are many factors that divide them. Religious belief falls into both camps. For some people, their religious faith is absolutely the core of their being: they could no more feel comfortable acting or thinking in a way that conflicted with their religious values than they could feel comfortable not breathing. For others, religious faith is either an irrelevancy-an historical anachronism-or positively harmful with many of the ills that befall humankind being placed at its door.
Religious believers need no arguments to be voiced in favour of taking religious values seriously, both generally and with particular reference to sexual ethics and behaviour. Agnostics and atheists might be tempted to ignore religious values but this would be a mistake. For a start, it is still the case that even in countries, such as the UK, where the national significance of religion is in decline, the majority of people when asked affirm a belief in God, including about a half of young people (McGrellis et al. 2000). Although a stated belief in God may not translate into any overt religious activity, such as communal worship, it often connects with what people feel about important issues in life and occasionally manifests itself, for example in wishing to get married in church (e.g. Davie 1994).
Then there is the fact that most of the world's religions, while they may not have anything very direct or clear to say about certain of today's ethical questions-such as the legitimacy of human reproductive cloning or globalisation-do have a great deal to say about sexual values. Religious values still permeate, for historical reasons, much of society and need to be understood. Of course, those with a religious faith also need to understand something of secular reasoning about sexual ethics: it is still too often the case that those with a religious faith assume that only they really know what is good sexual behaviour, and only they can put such knowledge into effect.