No spoilers in this thread since this one deals primarily with the 1st movie.
It's certainly a rail splitter amongst Terminator
fans. Was there ever a timeline where John Connor existed but his father was not Kyle Reese? Some say yes there was and it was only in alternate time loops that events changed and Kyle Reese ended up impregnating Sarah Connor instead of John Connor's original father. Others say that John Connor never existed without Kyle Reese. The first film is a self-contained predestination paradox where Skynet always sent the T-800 back to kill Sarah Connor, Kyle Reese always stopped it, and Kyle Reese always impregnated Sarah Connor.
Personally, I fall into the latter camp. How about you?