Arguments around these issues are generally the preserve of scientists. But there is a set of behaviors that is also inspected forensically and with evolution in mind, which extends far beyond the academy. We are a species that devotes enormous resources, effort, and time to touching each other’s genitals. Most animals are sexual beings, and the primary function of sex is to reproduce. The statistician David Spiegelhalter estimates that up to 900,000,000 acts of human heterosexual intercourse take place per year in Britain alone—roughly 100,000 per hour. Around 770,000 babies are born in Britain each year, and if we include miscarriages and abortions, the number of conceptions rises to about 900,000 per year. This means that of those 900,000,000 British encounters, 0.1 percent result in a fertilized egg. Out of every 1,000 sexual acts that could result in a baby, only one actually does. In statistics, this is classed as not very significant. If we include homosexual behavior, and other sexual behavior that cannot result in a pregnancy, including solitary acts, then the volume of sex that we enjoy magnificently dwarfs its primary purpose.