Okay so now try to see what happens when you mix this up. This is fiction so turn loose of your sensibilities. What would happen if you were to have a male persona inhabit a female body without a persona anymore. Or perhaps the other way around. Perhaps the term 'soul' would be easier for you to grasp. How much of what you identify as 'you' is dictated by your physical body and brain? Who can say really, but it's a fun concept to play with.
Transgressions, by Phillip Bernie did just that and did it very well and really quite tastefully. No bizarre erotic moments though there were some moments to be sure.
He took a male persona and put it in a female body. He even included cell memory as well as breed or race if you prefer. I found the study amusing though really there were relatively few actually funny spots. More along the line of a guy learning how to make use of the 'rack' he found himself endowed with.
This is the prevailing background thread through this story, but the story itself was captivating as the main character needed to protect his friends from an evil spirit and equally evil and ambitions people, even people who might have become powerful enough to consider themselves gods or their highest priests.
Yeah, we're talking magic here, and in the case of this story, magic is something like the Midi-chlorians of Star Wars, though perhaps less intelligent. In other words, particles with certain habits, visible only to the mage. Another very well handled thread. It's not easy keeping these things straight. Phillip Bernie did a very fine job with this book.