He looked at the book with pride. He had searched the entire city for this book, and now its finally in his hands, with this he could do whatever he wanted, and nobody would even know.
"Eh, I'll probably just use it to masturbate." He said to himself. There were no consequences whether he changed the world for good or for evil, so he might as well just let his fantasy go wild.
As he snuck into his apartment bathroom he thought what he'd want to change first. "Let's start with basics" he said "show me the pages on primary sex characteristics."
A long page of text was revealed to him, at the top was the most simple of all things, XX = vagina, XY = penis. This would be fun to play with. Time to make things a lot stranger, at least for the time being.