Found two stories of how Starburst might of been conceived by Twilight and Flash.

Sunset Shimmers Victory Lap or Twilight Punches Flash Sentry

Which one would be more plausible?

The latter

The one with the author who isn't a jerk

Twilight is the best and she deserves the best so the best story deserves to be the one to give her child. There said my piece.

Neither one really. The first story would suggest that Star's father is really human!Flash, which means that Twilight got together with Pony!Flash under false pretenses and is currently in some sort of loveless marriage with him. The second one is a kinda troll fic.

i would write a new one all together (but i suck at writing. i'm an art major)

Neither, really. If you want some better FlashLight clopfics, I could find them. Just assume at the end they decided to elope instead.

However, the actual conception went something like this, and that's that. You can't convince me otherwise, because that's definitely how hem going down on each other went down.