Kris Humphries -- And the Presumption is ... He's Kim Kardashian's Baby Daddy!

They've been separated for more than a year, but that don't matter much in California, where the husband of a pregnant woman is PRESUMED to be the father.

Translation -- Kris Humphries has the edge going in as Kim Kardashian's baby daddy. If he were to lay claim to the kid, Kim and Kanye would have to present "clear and convincing evidence" to a judge that Kanye did the dirty.

Fact is ... it wouldn't be hard to prove, since Kris hasn't gone near Kim for a long, long time ... and it appears the baby was conceived while Kim and Kanye were in Rome 3 months ago.

Nonetheless, there is a rebuttable presumption in Kris' favor, and Kim of all people should know a thing or two about re-butts.