Even though cultures and religions have designed repressive ways to 'cover-up' the subject, sex won't go away. It's the main function of the ego to be ready for that 'moment'. The preparation for that process is both internal and external, in that way we're robots to sex. Unconsciously we go through life propelled by our ego. She looks in the mirror, admires what she sees and conjures thoughts about how she'll get from him what she wants today.
Entire industries have been built to satisfy that market - it's a renewable resource.
Most people don't understand the first thing about nature, their motivations or themselves. Nature has designed everything in such a cleaver way so that it will fulfill its own ends - that of reproduction. But nature is the greatest comedian of all. A man and woman meet after long preparation. They are in tune with their times.