This is a collaborative research study led by University of Bonn IGSB and University College London, building on work from Yamashita et al (2020) and Poplin et al (2018), to assess the performance of humans at the task of differentiating male retinas from female retinas. This is a task, considered to be very hard for humans and even specialist ophthalmologists, but at which Artificial Intelligence (AI) is surprisingly good at. One of the purposes of the quiz is therefore to quantify human performance on this task, and to compare it to AI. Please do share the quiz with your colleagues, once you have completed it. We also encourage you to repeat the quiz multiple times to see whether you can improve your performance.