Neuroscientists have found an intrinsic biological difference between males and females in the molecular regulation of synapses in the hippocampus.
Any type of research which apparently reinforces preconceptions or conventional wisdom on a matter gets HUGE amounts of press, and it is a very difficult beast to control. The idea that men and women are fundamentally different is extremely alluring, especially if it has to do with how we think (we already know that we have different predispositions and reactions to say, physical work...testosterone makes a difference). I fell bad the authors of this study have to go to such lengths to clarify that their study doesn't say much about differences in cognition, just in response to medications (and hormones). Mostly because I don't think they'll be heeded by the press. Anyway, it's an interesting study, and the whole oncoming era of more personalized medicine is exciting, especially with regards to better understanding the brain and perhaps being able to better prescribe medications for mental disorders (as opposed to our somewhat trial-and-error based method that is frequently used today).