Since the fall of Adam and Eve none of humanity comes here to this place in the spiritual appearance, but the physical appearance only.

They will not be two men. one maintaining a feminine spirit and the other a masculine spirit, They will be physical in appearance and be of the gender in which they appear. Just as it was with Adam and Eve in the beginning after the fall. God is operational from backwards to forwards. When they (Adam) (Eve) first came into the world they were spiritual, at their departure they appeared physical, as their gender did appear. So also those two witnesses/Prophets, when they came will appear in the physical gender they identify with, and after their departure, once again spiritual.

For the word prophets in describing the two witnesses in, (Rev.11KJV.) Is interpreted in the Greek vernacular, as either prophet (male) or/and prophetess (female,) (Strong Concordance.)