Plato Symposium 189c
In the first place, let me treat of the nature of man and what has happened to it; for the original human nature was not like the present, but different. The sexes were not two as they are now, but originally three in number; there was man, woman, and the union of the two, having a name corresponding to this double nature, which had once a real existence, but is now lost, and the word "Androgynous" is only preserved as a term of reproach. In the second place, the primeval man was round, his back and sides forming a circle; and he had four hands and four feet, one head with two faces, looking opposite ways, set on a round neck and precisely alike; also four ears, two privy members, and the remainder to correspond.
Genesis Rabbah 8:1
Aggadah... R. Jeremiah b. Leazar said: When the Holy One, blessed be He, created Adam, He created him as androgynous for it is said, ‘Male and female created He them and called their name Adam’ (Gen. V, 2). R. Samuel b. Nahman said: When the Lord created Adam, He created him double-faced, then He split him and made him of two backs, one back on this side and one back on the other side. To this it is objected: But it is written, ‘And He took one of his ribs, etc.’ (Gen. 1, 21). ‘Mi-zalothaw’ means one of his sides, replied he, as you read, ‘And for the second side (zela‘) of the tabernacle, etc.’ (Ex. XXVI, 20)....
Notes and References
"... Many early interpreters of the Bible believed that Adam was androgynous. This idea is also found in Plato (Symposium 189c-193e) and was discussed in rabbinic circles (Genesis Rabbah 8:1; b. Meg 9a). Recent studies of gender across the sciences and humanities reveal its formidable complexity, so we should not be surprised by the complexity and ambiguity of the biblical presentation of adam. Some texts seem to be deliberately ambiguous on this point. The sudden shift to the first person plural that accompanies God’s announcement of the creation of humankind in Gen 1:26 (“Let us make adam in our image, according to our likeness,” italics added) could certainly be associated with an emphasis on male and female. Some biblical scholars view this as a reflection of the divine council scene, a stock image in the ancient Near East. But it was common in ancient Near Eastern traditions to express origin stories in terms of male-female complementarity (for example, Enki and Ninmah, Enki and Ninhursaga; Atrahasis [Assyrian version]; compare Tiamat and Apsu in Enuma Elish and other myths featuring theogonic pairs). The principle of complementarity may also be behind the formula that follows: “In the image of God he created him; male and female he created them” (Gen 1:27, italics added, RSV; compare Gen 5:1-2). In Gen 2, the woman (Hebrew, ishshah) and man (Hebrew, ish) are two sides of the human whole. The play on words also keeps with the notion of complementarity. The first-century commentator Philo thought that Gen 1 described the androgyny of the initial generic human figure, while Gen 2 focused on the physical differentiation of male and female from a single physical entity. Ultimately, to restrict the person Adam to a particular male, or to a notion of “maleness,” is to miss the complexity built into the first human person ..."
Callender, Dexter Adam (p. 1) Society of Biblical Literature, 2017