What do women want? It has been at the centre of numerous books, articles and blog posts, and no doubt the cause of countless agonised ponderings by men and women alike. But despite decades spent trying to crack this riddle, researchers have yet to land on a unified definition of female desire, let alone come close to fully understanding how it works. Now, scientists are increasingly beginning to realise that female desire cannot be summarised in terms of a single experience: it varies both between women and within individuals, and it spans a highly diverse spectrum of manifestations. But more recent evidence reveals that differences between the sexes may actually be more nuanced or even non-existent, depending on how you define and attempt to measure desire.