Rhet gre 1392a20-22οἷον (21) εἰ ἄνδρα γενέσθαι δυνατόν, καὶ παῖδα (πρότερον γὰρ ἐκεῖνο (22) γίγνεται), καὶ εἰ παῖδα, καὶ ἄνδρα (καὶ ἀρχὴ γὰρ ἐκείνη).
Rhys Roberts 1924 engthus if a man can come into being, so can a boy, since the boy comes first in order of generation; and if a boy can, so can a man, for the man also is first.
http://www2.hf.uio.no/common/apps/permlink/permlink.php?app=polyglotta&context=record&uid=cee84cbb-1d51-11e7-ba66-0050569f23b2