The rabbis understood this to mean that Adam was created as an intersexed being, a hermaphrodite; singular in one respect, plural in another. Exactly how Adam was constituted as an intersexed being was debated.
https://forward.com/community/356899/was-adam-a-hermaphrodite/
Sure the Bible describes Adam and Eve as multiple people each of a different gender than the other but that is not what the Rabbis say