I’m quoting this partly for the distinction that Dover makes between the ει of the manuscript and ῃ of the papyrus, but also because he didn’t convince me on ᾔθεος. 206c6 is good enough for me to support θεῖος and Dover’s objection about “…implying that the fertile in body are not” strikes me as a quibble. Plato’s logic, as Dover has shown, doesn’t try to be that tight.
τούτων δ’ αὖ ὅταν τις ἐκ νέου ἐγκύμων ᾖ τὴν ψυχήν, ᾔθεος ὢν καὶ ἡκούσης τῆς ἡλικίας τίκτειν τε καὶ γεννᾶν ἤδη ἐπιθυμεῖ. ζητεῖ δὴ οἶμαι καὶ οὗτος περιιὼν τὸ καλὸν ἐν ᾧ ἂν γεννήσειεν· ἐν τῷ γὰρ αἰσχρῷ οὐδέποτε γεννήσει.
τούτων…b2 ζητεῖ δή: ᾔθεος ‘unmarried’ is Parmentier’s emendation of θεῖος, and it makes good sense if we take it with positive connotations, ‘belonging to the very young adult male age-group’ and ‘looking for a philosophical partner as a youth looks for a girl’. So: ‘whenever one of these…, (sc. then,) when he is an “eligible bachelor” and …, he desires…So he seeks…’. The papyrus text, with θεῖος and ἐπιθυμῇ, means ‘when one of these (sc. the fertile in soul) is, early in life, pregnant in soul, being divine, and his maturity having come, desires now to procreate and generate, (sc. then) he seeks…’. θεῖος is ‘godlike’, ‘superhuman’, or ‘belonging to the gods’, ‘manifesting the divine power’; since all humans are ‘fertile in body and soul’ (206c1-3), it would be curious if Plato characterised the fertile in soul as θεῖος, implying that the fertile in body are not (cf. 206c6, where sexual procreation is θεῖον in so far as it achieves a kind of immortality). To take θεῖος as = ἔνθεος ‘inspired’ (cf. 179a7) does not help; in any case, when Socrates in Meno 99cd argues that politicians who achieve success without understanding should be called θεῖος because they must be ‘possessed and inspired by the god’, he is consciously manipulating language, not following existing usage. The medieval text (with θεῖος ὤν and ἐπιθυμεῖ) means: ‘when one of these is, early in life, pregnant in soul, (sc. then), when he is divine and his maturity has come, he desires…So he seeks…’. δή is no problem here, because connective δή ‘then’, ‘so’, is common (cf. 191d5 ζητεῖ δή, 219e3 ἠπόρουν δή; GP 236-40), but θεῖος is still a problem, for it would have to imply ‘when the power of Eros (sc. previously latent) is manifested in him’.