Athenaeus here is discussing the myth that Helen was hatched from an egg. It seems that there was some belief in extra-terrestrial life among the ancients.
οὐκ εὖ δὲ Νεοκλῆς ὁ Κροτωνιάτης ἔφη ἀπὸ τῆς σελήνης πεσεῖν τὸ ᾠὸν ἐξ οὗ τὴν ῾ Ἑλένην γεννηθῆναι: τὰς γὰρ σεληνίτιδας γυναῖκας ᾠοτοκεῖν καὶ τοὺς ἐκεῖ γεννωμένους πεντεκαιδεκαπλασίονας ἡμῶν εἶναι, ὡς Ἡρόδωρος ὁ Ἡρακλεώτης ἱστορεῖ.
Neocles from Crotona was wrong to say that the egg from which Helen was born fell from the moon. For moon women lay eggs and those who are born there are fifteen times as big as us – as Herodorus of Heraclea recounts.