I think that this is the important point. I used to study and work in psychology/neurobiology, and I’ve gone out of my way to read some of the studies that get thrown around to support “gendered” brains. These studies do not make any real assertions about gendered feelings or behavior. They simply point out that there may be structural differences between male and female brains. Is it possible that structural differences do, in fact, influence or correspond to gendered behavior? It’s possible. But it’s also possible, like you said, that it’s on a small scale or makes no difference at all. To say that these studies prove that there is such a thing as a girlbrain or boybrain is taking it one (or several) steps too far and misrepresents the findings.