if you take into account that the conversation that anakin and palpatine had in revenge of the sith was odd but. Palatine never revealed to anakin who his father was but when you look at the look at palpatines face when he mentioned midichlorians. Anakin was conceived by Darth plagues and impossible to be the son of watto and if you remember back in phantom menace shmi said I carried him and I gave birth to him. Now if you look at episode 2 clone wars padme wasn't pregnant yet. so when anakin returned to coruscant with palatine in tow and you notice that she is pregnant after she tells anakin that something wonderful has happened she is going to have a baby little did they know that they would be twins luke and leia but when Vader choked padme almost killing her but the force runs strong in the family. so it doesn't matter who anakins father is we only know that he was born of the force.