There’s this line of dialogue from the rough draft, spoken by General Luke Skywalker to Annikin Starkiller:

“You are trained well, but remember, a JEDI must be single-minded, a discipline your father obviously never learned, hence your existence.”

So from early on, Lucas entertained the notion that celibacy was valued by the Jedi. That said, it wasn’t a hard-and-fast rule that Jedi were dogmatically required to adhere to; there’s nothing in the rough draft implying Skywalker held Kane Starkiller in contempt for siring offspring.

My memory of the second-to-third drafts in much hazier, but I recall a mention that in their prime, the Jedi consisted of several hundred families. Again, an indication that celibacy wasn’t a inviolate rule until the prequels were made.