WEIRD sex: How a package of Western sexual norms facilitated social control, fuelled racism and colonialism, messed up sex lives and is creating untre

Why are bugs that are transmitted by sex so stigmatised? Why are they classified as "e;essential pathogens"e; that should be eradicated wherever they are found, when far more pathogenic bugs that are not transmitted by sex are classified as less pathogenic? Why do people with STIs typically have to be treated in separate health facilities? What is the basis for the West's insistence that monogamy is "e;natural"e; and polygamy "e;backward"e;? WEIRD Sex argues the answer doesn't come from biology. It comes from a millennium of Western moral engineering hiding in plain sight as science.We think of our sexual morality as common sense, and our disease classifications as neutral biology. WEIRD Sex shows both are inheritances from a specific culture - Western, Educated, Industrialized, Rich, Democratic (WEIRD) - that got exported to the entire planet through empire, medicine, and law. It was then mistaken for human nature itself.Tracing a "e;cultural ratchet"e; that runs from medieval church reform through the Enlightenment, colonial conquest, and Cold War-era science, the book identifies six pillars that fused into a single, self-reinforcing package: sex-negativity, mononormativity (the belief that monogamy is the most ethical form of partnering), heteronormativity, gender essentialism, sexism, and anti-miscegenation. European empires didn't just conquer land - they criminalized local sexualities, erased third-gender traditions, suppressed polygamy, and weaponized STI panic to brand colonized peoples as "e;immoral"e; and in need of control. Then, in a final twist, the West liberalized at home in the 20th century and began lecturing its former colonies for the very conservatism it had imposed on them.The same moral DNA, the book argues, shaped one of modern medicine's biggest blind spots. When germ theory arrived, scientists didn't discard old ideas about sinful sex - they relabeled them, branding certain microbes as inherently dangerous "e;essential pathogens"e; simply because of how they spread. That century-old moral judgment still drives today's STI policy, including the mass screening of people with no symptoms — a practice this book shows is scientifically unfounded, damages the microbiome, accelerates antibiotic resistance, deepens stigma, and hasn't reduced STI rates.So what actually drives outbreaks? Not poverty. Not genetics. Not individual virtue. WEIRD Sex lays out the epidemiological case that it's sexual network structure - and particularly concurrency, the overlap of partnerships in time - that determines whether an infection fizzles out or explodes through a population. This single mechanism explains disparities that moralizing never could: why certain regions, certain communities, and certain groups have dramatically higher STI burdens.The book closes with a genuine alternative: an ecosocial framework for sexual health that replaces fear and punishment with network science, consent, pleasure, microbiome protection, antibiotic stewardship, and community-led solutions - a way to finally treat sex like biology instead of sin.