Men and women are different, of that there is no doubt. In neuroscience, there has been a lot of research into these differences, as they relate to treating neurological disorders. Women are more likely to have Alzheimer’s, depression and anxiety, so if scientists could find biological brain differences, that could be a path to finding treatments for some diseases. One factor that complicates the issue is that in neuroscience research, there are five times more male animals being studied than female. Part of the reason is that female lab rats go into heat every 4 to 5 days and that can mess with controls in studies, however, there still needs to be more research into sex differences.
Male brains are bigger in size and volume than females, but that is largely due to men having bigger heads. A 2018 study at Oxford did show some differences in cortical thickness between men and women. Controlling for size is possible in some research, but it tends to change the results and so far, not much is conclusive. When relative size is compared there are some anatomical differences, but again, the research was not that specific. A 2015 study showed that most brains are a “mosaic” of male and female traits.