TheGreatElvenWarrior, you made an interesting assumption about Sauron being an '
asexual being'. Would you think the same thing applied to the Ringwraiths, after they became wraiths? Perhaps these were actual topics of debate among loremasters in Middle-earth.
On a more down to earth level, I've thought that if Gondorian soldiers were more like those of WWI and WWII, they would have asked the Nazgul, and in particular their leader, about when they were last sexually active. Also, the Ringwraiths would be asked about their Dark Lord, about whether he had certain organs, and if he ever used them, or if they were just for decoration.