Another excellent post Alexander! You might be interested to know that a lot of great work in C. elegans (my favourite model organism) has be been done in understanding male and female (or hermaphrodite in C. elegans) brains. This model organism has a simple nervous system but there are male and hermaphroditic specific behaviours. C. elegans provides researchers a resolution at the level of neuronal connectivity the differences in sexes. There is some nice genetic work in C. elegans where you can sex reverse the brains of males or hermaphrodite (ie. female brain in male and male brain in females) and alter behaviour.
Cheers!
ian