Kourtney Kardashian -- DNA PROOF Scott Disick's My Baby Daddy

Kourtney Kardashian is putting the rumors to rest that she conceived 3-year-old Mason after cheating with a male model, releasing DNA test results Thursday that show Scott Disick is really the father.

TMZ broke the story ... a male model named Michael Girgenti is suing Kourt for paternity over Mason, saying he had sex with her in '09 and 9 months later she popped out a kid.

KK immediately denied the allegations as a grab for fame -- but now she's got hard proof ... a lab doc that says the probability that Scott is the dad is 99.99% ... meaning the male model is 99.99% full of it.