They're claiming that they can predict sex, not gender. The study does comment on a trans case in their validation-set, which of 1,287 images, had 1 image for

They're claiming that they can predict sex, not gender. The study does comment on a trans case in their validation-set, which of 1,287 images, had 1 image for someone whose genetic-sex and reported-sex didn't match. For that 1 image, the algorithm's prediction corresponded to the genetic-sex rather than the reported-sex. > Genetic sex was discordant from reported sex in one validation set image, and this image was incorrectly predicted by the model; that is the model predicted sex consistent with genetic sex in this case (Table S1). Table S1 can be seen in the Supplementary Information linked near the bottom of [the article](https://www.nature.com/articles/s41598-021-89743-x https://www.nature.com/articles/s41598-021-89743-x). It really doesn't show much data though. --- As for the excerpt you quoted about predicting gender, the authors were writing about the claims from [a different (and pay-wall'd) study](https://www.nature.com/articles/s41551-018-0210-5 https://www.nature.com/articles/s41551-018-0210-5).