Brain Sex
There appears to be a male and female pattern of psychosexual behaviour. These are modes of behaviour — one male, one female which are laid down, like Brain Gender, in early life and seem to be independent of environment (how, where, and by whom we are raised) and can be independent of both Physical Gender and Brain Gender.
Before I delve into what Brain Sex is, let me state what it is not — it is not sexual orientation. While sexual orientation can be an attribute of Brain Sex, it is not a primary one. More on this later.