I found myself increasingly frustrated as I read the book with Magnet’s treatment of gender. When Biometrics Fail only name-drops transphobia and barely touches upon queer marginalization a couple of times, primarily in the introduction and the first chapter; furthermore, When Biometrics Fail almost seems to conflate sexuality and gender, particularly on page 60 in the discussion of a lesbian’s butchness being criminalized, where butchness might better be understood as a facet of gender rather than a facet of sexuality. At the same time, When Biometrics Fail indicates that part of the failure of biometrics is the inability for technology to classify and code something as dynamic and fluid as the human body—the failure is already written into the science itself, as the human body becomes essentialized into a static form that can be quantified and broken down into logical constituent parts when it in fact is fundamentally the opposite.