SOME OF YOU BITHS DO NOT NEED TO EVER QUESTIONS US AGAIN! NEVER, EVER!
Especially Darth Plagueis. — yes, a LEGENDS canon book.
For the TL:DR short bus: The Intergalactic Banking Clan has always been run by Muuns on Muunilinst and Scipio and Aborah. Aborah was the labs of a Hego Demask (aka Darth Plagueis – aka Darth Sidious or Sheev Palpatine’s master) where the midi-chlorians were manipulated to cause pregnancies through the Force. But Sidious must not have been able to complete the experiment. So he was unethical about it. What a dark side Force user were do – cut corners to win.
And so… It wasn’t natural. Palpatine isn’t the father. But it is quite conceivable that Kanan’s sperm was selected in a eugenics experiment…