NEWS AND VIEWS 25 March 2026 A type of childhood brain tumour called ependymoma is more common in boys than in girls. The reason for this difference turns out to be sex hormones such as testosterone. By Najla Kfoury-Beaumont Najla Kfoury-Beaumont is in the Department of Neurological Surgery, University of California, San Diego, California 92037, USA. Sex differences in the incidence and outcome of numerous diseases, including brain tumours, are evident regardless of age and demographics 1 – 4 . A type of childhood malignant brain tumour called posterior fossa type A (PFA) ependymoma has an average age of onset of around 3 years and is more prevalent in boys than in girls 5 , 6 . Boys are not only more likely to get the disease, but they also have a worse prognosis and significantly shorter overall survival time than do girls 5 , 6 . Writing in Nature , Zhang et al .…