Los Angeles, California - Khloé Kardashian's baby Tatum looks a lot like her brother Rob... so much so that she had Tristan Thompson take multiple paternity tests to make sure the basketball player was the baby's actual biological father!

Khloé is wild for this one.

In her Tuesday episode with the SHE MD podcast, KoKo confessed to being spooked by the "freaking weird" resemblance her son has to her brother Rob in both looks and mannerisms.

"My son looks just like my brother," Khloé dished.

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"Because he was an IVF baby or a surrogate baby, I was like, 'Rob, have you ever donated sperm somewhere?'"

Fearing that somehow her brother, Robert Kardashian Jr., had gotten a sperm donation mixed up with Tristan's for the surrogate-born baby, The Kardashians star made her ex take three paternity tests!

She joked that Tristan was "so offended" by the suggestion, but Khloé had the perfect response: "In this family, that wouldn't surprise me, but that would be so disgusting."

The Good American founder shares daughter True (5) and son Tatum (21 months) with ex Tristan, who was embroiled in several extremely public cheating scandals during their relationship.