It would have been impossible for Luke to think Dane was his son. In the original Thorn Birds, Luke had seen Meggie just prior to giving birth to Justine. Luke had never seen Justine until several months later when Meggie brought her to Luke's barracks. Meggie had not seen Luke during this time as she comments to Luke at the barracks that he had never seen Justine. By this time she was already pregnant with Dane. After their meeting at the barracks, Meggie went with Justine to Drogheda. 20 years later, Justine makes a comment that she should look up Luke sometime.