Gender identity ideology is about more than Twitter storms and using the right pronouns. In just 10 years, laws, company policies, school and university curricula, sport, medical protocols, and the media have been reshaped to privilege self-declared gender identity over biological sex. People are being shamed and silenced for attempting to understand the consequences of redefining "man" and "woman". While compassion for transgender lives is well-intentioned, it is stifling much-needed inquiry into the significance of our bodies.

Most Americans do not understand the real threat that the “transgender” agenda, or the so-called “gender identity” movement, poses to all of us—especially women and girls—nor do they understand the extent to which it is taking over US law and civil society. The simple truth is that “gender identity” functions to abolish sex, and all of our civic institutions—government, media, academia, and business—have been completely captured by it.

Material Girls is a timely and trenchant critique of the influential theory that we all have an inner feeling known as a gender identity, and that this feeling is more socially significant than our biological sex. Professor Kathleen Stock surveys the philosophical ideas that led to this point, and closely interrogates each one, from De Beauvoir's statement that, 'One is not born, but rather becomes a woman' (an assertion she contends has been misinterpreted and repurposed), to Judith Butler's claim that language creates biological reality, rather than describing it.

On the face of it, women's sport is on the rise, garnering more attention and grassroots involvement than ever before. However, the truth is that in many respects progress is stalling, or even falling back. Sharron Davies is no stranger to battling the routine sexism the sporting world. She missed out on Olympic Gold because of blatant doping among East German athletes in the 1980s, and has never received justice. Now, biological males are being allowed to compete directly against women under the guise of trans 'self-ID', a development that could destroy the integrity of female sport.

Teenage girls are taking courses of testosterone and disfiguring their bodies. Parents are undermined; experts are over-relied upon; dissenters in science and medicine are intimidated; free speech truckles under renewed attack; socialized medicine bears hidden consequences; and an intersectional era has arisen in which the desire to escape a dominant identity encourages individuals to take cover in victim groups. Every person who has ever had a skeptical thought about the sudden rush toward a non-binary future but been afraid to express it - this book is for you.