These problems, less pressing when the subject is a dead fish, take on outsize importance when potentially flawed research is used to validate, medicalize or deny human identities. Attempts to dispel fears by way of etiology enshrine an imperfect science as the basis for our rights. Our society already polices access to gendered spaces and transition-related care, and the notion that someone might not be “trans enough” enables individuals and institutions to disregard those who don’t meet an arbitrary standard.

The hunt for precise biological markers could radically alter people’s lives, especially if given such cultural currency — yet even trans-friendly outlets and journalists have been quick to make the jump from small-scale studies to the fantasy of brain scans that can reveal your gender. Julie Bakker, whose lecture at the European Congress of Endocrinology sparked conversations about such a diagnostic, pushes pushes back against this application of her research, though she understands the desire for an easy answer: “We work a lot with children and adolescents, and we had parents who were hoping that we could look into the brain of their son or daughter and say, ‘Okay, we can actually see that your son’s brain is not ‘male-like,’ so that’s explained.’ ” But, she told me, “it’s not going to work like that. There’s no such thing as a ‘100 percent male’ man or a ‘100 percent female’ woman — we all have some masculine or feminine traits.”