ATMachine said:
Pfluegermeister at TFN notes that in the November 1, 1981 revised second draft of ROTJ, Luke delivers this line to the Emperor:
"Never! Never will I turn to the dark side. You have failed, your highness. I am a Jedi as my father was before me, and as his father was before him."
The November 1 revised second-draft script was one where Lucas took Kasdan's typewritten second draft and added his own handwritten revisions. Thus, Lucas himself was responsible for this line.... which entirely excludes the possibility of a virgin birth for Anakin.
But since it isn't in the movie, what's your point? That Lucas should commit to ideas that ended up on the writing room floor?