Khloe welcomed her son via surrogate in July 2022.
Last month, the reality star shared Tatum's name with the world during an episode of The Kardashians. "His name is Tatum. So Tatum and True," Khloe shared in a confessional interview, adding, "Naming a human is really hard."
Now, Tatum's last name has been abuzz after TMZ reported that Khloe initially gave her son Kardashian as his legal last name. The outlet's sources say Khloe eventually decided to change his name to Tatum Thompson, and that's now his legal name moving forward.
However, a source tells ET that Tatum's last name was automatically Kardashian after his birth because Khloe and Tristan are not married.
"When a baby is born and a name has not been chosen, something still must be submitted to the state, and the state will make a birth certificate for 'baby’ with the mother’s last name if the couple is not married," the source explains. "Since then, Khloe and Tristan's son's name was legally made Tatum Thompson."
Khloe and Tristan also share a 5-year-old daughter, True, whom they welcomed in 2018.
Khloe welcomed her son via surrogate in July 2022, and his hospital birth was documented in the season 2 premiere of The Kardashians. She previously shared that the little guy looks like her brother, Rob Kardashian, but that she wanted him to have a "T" name like True.
The subject of her son's inception and birth have been difficult for Khloe, who previously claimed that Tristan "encouraged" her to do the embryo transfer days before the news broke that he had fathered another child with another woman, Maralee Nichols, while engaged to Khloe.
On a recent episode of The Kardashians, Khloe admitted that she has struggled with the surrogacy process, telling Scott Disick that she feels less connected to her son than she did to her daughter.
"I definitely buried my head in the sand during that pregnancy, that I didn't digest what was happening," Khloe noted. "I think when I went to the hospital, I think that was the first time that it really registered. I think it has nothing to do with the baby."
"I definitely was in a state of shock from my entire experience in general," she added of her time in the hospital welcoming her son. "I felt really guilty that this woman just had my baby and then I take the baby and I go to another room and you're just sort of separated. I felt it's such a transactional experience... I wish someone was honest about surrogacy and the difference of it. But it doesn't mean it's bad or good. It's just different."