Forget about casual sex, it’s all about love. It does not exist argues a scientist! Helen Fisher, biological anthropologist and author of ‘Anatomy of Love’, says sex triggers the brain regions to love and attachment. She claims there is no such thing as casual sex. She argues that up to 35 per cent men and women having a one night stand end up in along term relationship, is a strong indicator that her theory of casual sex being a a myth is true. Fisher speaks of three distinctive brain systems for mating and reproduction that are interrelated to each other and help us fall in love.