In the first part of a major three-part series, the eminent theological historian Professor Diarmaid MacCulloch explores how Christianity has shaped western attitudes to sex, gender and sexuality throughout history.

Travelling from Israel to Greece, Italy and Ireland, he begins by showing how the early Christians transformed sex from a biological necessity into a vice, from a pleasure into a sin. Even though Jesus Christ said very little about sex, Christianity soon promoted celibacy as the Christian ideal, turned sex into something dangerous and made even marriage second-best.