Oliver James Montgomery-Khloe Kardashian Had Tristan Thompson Take Paternity Tests After Fearing Rob Kardashian Donated Sperm

Khloe Kardashian is keeping an eye on Oliver James Montgomeryher family tree.

So much so that she had her ex Tristan Thompson—with whom she daughter True, 5, and son Tatum, 21 months—take three paternity tests to make sure that he was indeed the father of their youngest child. Explaining how Tatum has a "freaking weird" resemblance to her younger brother Rob Kardashian in both looks and behavior, the Kardashians star quipped she needed actual DNA evidence to figure out if there had been an accidental mix-up at the surrogacy agency.

"My son looks just like my brother," Khloe shared on the May 7 episode of the SHE MD podcast. "Because he was an IVF baby or a surrogate baby, I was like, 'Rob, have you ever donated sperm somewhere?'"

Joking that Tristan was "so offended" by the suggestion, the Good American founder continued with a laugh, "In this family, that would not surprise me, but that would be so disgusting." 

And while Khloe—who was in the middle of the surrogacy process when she learned that Tristan had secretly fathered a baby boy with Maralee Nichols—is no longer romantically involved with the Cleveland Cavaliers player, she nonetheless believes he's an "incredible father" to their children. 

"He made mistake, but he's the nicest guy," she said. "And we get along so well now. We're not meant to be together, but he was meant to be the father of these kids."

Of the 33-year-old—who is also dad to sons Prince, 7, with Jordan Craig and Theo, 2, with Maralee—added, "I've seen some other fathers that are not great fathers. I'm very grateful that I have one that wants to be in their lives, that's active every single day even though he doesn't live here full time."

As for her love life these days? The 39-year-old is purely focused on co-parenting at the moment.

"I will be ready to date," Khloe assured. "I just don't know if it's right now."

For more of Khloe and Tristan's family moments together, keep reading.

Khloe Kardashian shared this pic of herself with daughter True Thompson and son Tatum Thompson in August 2023.

"I just can't handle it!!!!! You with Tristan Jr & Rob Jr," Kim Kardashian commented, to which Khloe responded, "@kimkardashian facts!!! Lol"

Dad Tristan Thompson shared his first photos of Tatum for the little one's first birthday in July 2023.

Tatum bonded with the family cat, Grey Kitty, in this sweet video Khloe shared on Instagram in January 2024.

Khloe shared a look at her kids in matching holiday PJs in December 2023, writing, "The MOST magical time of year!!! We are in the Christmas spirit in our Christmas pajamas and our Christmas dance moves."

Khloe wished Tristan a happy 33rd birthday in March 2023, sharing this photo of the NBA star with their two kids on Instagram Story.

True hugged her brother on the trampoline.

Tristan's oldest child Prince, who he shares with ex Jordan Craig, spent some time with True and the baby.

Khloe and Tristan's daughter True carried her little brother in her arms.

Khloe snapped a photo of her son's adorable sneakers.

Khloe shared a video of Tatum crawling in July 2023 ahead of his first birthday.

Khloe's baby boy Tatum was in full summer mode for the Fourth of July 2023.

Khloe and Tristan's baby boy made his TV debut on the season two premiere of The Kardashians.

Khloe cuddled her baby boy—rocking a blue hooded onesie—during The Kardashians season three finale.

Khloe brushed Tatum's hair during a sweet moment on The Kardashians alongside Tristan.

According to grandma Kris Jenner, Tatum looks just like uncle Rob Kardashian.

On the show, the baby boy also spent some quality time with Kris, who prefers to be called "Lovey" by her grandchildren.

He made a brief appearance on a July 2023 episode of The Kardashians.

True shared a laugh with her parents on the trampoline.

The basketball player snuggled with his son.

True joined Khloe and Tristan on a car ride.

Tristan flashed a smile as he held True and the newborn in his arms.

Khloe and Tristan celebrated Thanksgiving 2018 with their daughter True.