Ben 10,000's daughter seems like a case of the Mandela Effect
Tactical Ochoa last edited by Tactical Ochoa
For those who don't know, the Mandela Effect is a phenomenon where people recall an event/memory that never actually occurred or turned out to be false. An example of this is the children book series, The Berenstein Bears…except it's not Berenstein with an "e" near the end, as many had believed. It's actually Berenstain with an "a" near the end.
In regards to the Ben 10 series, at least from what I've heard, many Ben 10 fans (and sure, even I) believed that Ben 10,000 had two kids, Ken Tennyson and Gwendolyn Tennyson, as confirmed through a Pop-Up Trivia from the Ken 10 episode. However, if these images from the Ben 10 Planet Wiki are accurate and cover all the pop-ups from that very episode, there is no pop-up that confirms that Ben has a daughter.
To further add to this, Thomas Perkins tweeted back in January 2021 that as far as he knew, Ben didn't have a daughter and that Ken was an only child.
There does seem to be one "official" source that does state that Ben has a daughter, as shown below. Granted, I say "official" with quotation marks because one, this isn't ever established in any of the shows and two, I have a feeling that this was made under the very Mandela Effect that I'm explaining here as well. Although, this does also refer to the Ultimate Alien version of Ben 10,000 and not the Original Series version.
Due to this, I don't think that Ben 10,000 really does have a daughter and that the pop-up trivia that states this actually exists. However, if anyone does have an actual image of the Ben 10,000's daughter pop-up trivia, feel free to share it here. Granted, I would likely not buy into this anyways because I usually prefer for things to get established in-universe and not through an outside statement. In the case with the Pop-Up Trivia episodes in the Original Series, I did not like how some of the pop-ups tried to create and establish lore within the Ben 10 universe that wasn't proven in-show. Either way, feel free to provide an image that does prove that the Ben 10,000's daughter pop-up does indeed exist if anyone is able to find it.
Note: The sources linked here and the Ben 10,000 info image can be found on the link embedded in "Gwendolyn Tennyson" and the link to the images of the Ken 10 pop-ups can be found here.