What Clues cue meneleus and Helen that Telemachus is Odysseus son?

Meneleus and Helen recognize Telemachus as Odysseus' son primarily through his resemblance to his father, particularly in his appearance and demeanor. Additionally, Telemachus' demeanor and the way he carries himself evoke memories of Odysseus, reinforcing their connection. Helen also recalls the prophecy that Odysseus' son would come seeking news of his father, which further confirms Telemachus' identity.