in physics they call it a spontaneous break in symmetry. "almost symetric/perfect" is usually more tantalizing and beautiful than actual perfection. Like Eva Mendes' mole. It makes her face less flawless, but arguably more beautiful. This phenomenon might explain the situation you are talking about. Although in this case, the spontaneous break in symmetry should be that the TS is genetically male and has a penis. Any other break imo is bad and makes her less attractive. That's just me though.