Are we naturally monogamous, or do we have a natural tendency to desire to have sex with more than one partner? Is homosexuality only present in humans, as it is often said? Do men have more sexual desire in general than women, as often portrayed in popular culture? Who has more often multiple orgasms, and tends to be more sexually fluid, women, or men? And are such traits socially constructed, as are many of the so-called gender differences - such as girls preferring pink and boys blue -, or do they reflect a true biological evolutionary difference between men and women? And how do intersexuality, marriage, having kids, and romantic love, and the origin of honeymoons and wedding rings, fit into all this? Although these topics are widely discussed and commercialized within our societies, from dating apps to Bollywood movies, most of the conversations about and depictions of them are based on biased stereotypes contradicted by scientific and historical facts. Diogo, a multi-awarded biologist and anthropologist, provides for the first time a discussion of these topics based on historical and scientific data from fields such biology, anthropology, sociology, and psychology, that is accessible to the broader public. Importantly, he shows that there is often a marked conflict between what people truly desire and how they are supposed to behave based on prevailing stereotypes and social norms - a conflict that, unfortunately, commonly leads to sexual, and eventually to life, dissatisfaction. The book aims to bring awareness about these topics and contribute to a less prejudiced and tabooed, and more naturalistic, public discussion about them.