Reitama's manga / #Selfcest(1)

I was thinking (this is just a theory...) - since he's occupying the body of a 16 year old girl, and (probably) in a parallel dimension* and the consciousness of the 16 year old girl went to his original body in his parallel dimension. *Referring to "But there wasn't anything built here back then..." in Ch. 2 Pg. 8