Tafsir of Al-Qiyamah 75:39

"And made of him"—meaning, of man; and it has been said: of the semen—"the two mates," meaning the two categories: the male and the female. [The male and female] are a substitution for "the two mates," and the hermaphrodite does not transcend these two. Zayd ibn Ali recited it as al-zawjan (with an alif), according to the dialect of the Banu al-Harith ibn Ka'b and those of the Arabs who agree with them, in that the dual is [inflected] with an alif in all of its states.