I know this question is as old as lion king itself but did you think that "fluffy" was a boy or a girl?

The cub remains genderless. I had those cards myself and I was confused too. But the filmmakers never referred Kopa as the cub, they just added "son" before TLK 2 was in production even when the cub had no gender reference. Disney in 1993 preferred it as "The Cub" and not calling it a she/he before the film was released. From the books or comics the cub is called a son. the film it's self has the cub with no gender. and TLK 2 books and and many others called the cub a she. The cub was never a male officially but genderless. Disney made it clear that Fluffy is Kiara. Void the comics/books/cards because it's not the actual gender of Fluffy, they made it into a boy only because they're weren't sure if there's gonna be a sequel yet at the time. Fluffy is never a male but a genderless/Kiara. This cub is officially her but it's her original design and now TLK books and cards today referred the cub a girl.

I think Fluffy was neither. I assume they had it have characteristics of both a female and a male for a reason, and I'm supposing that reason being so we wouldn't know directly away their kid is going to become important in a plausible sequel. Adding, I'm going to be honest here, what kind of name is Fluffy? I'm pretty sure two wild lion parents wouldn't name their kid Fluffy.

SORRY MY KEY BOARD IS MESSED UP IM NOT YELLING BUT IM REALLY NOT SURE NOW BECUASE THEY HAVE A NEW CUB NAMED KION AND AS FOR KOPA STILL DOESNT APPEAR IN TLK MOVIES

I personally never gave a moment's thought to the cub's gender or sex when growing up. Or at least I don't remember doing so. Until I found the online fandon as an adult and all those fan theories and the whole Kopa craze to exist. I was very surprised to learn that so many fans cared about the cub's gender/sex and even specifc identity from the very release of the film. I mean, so much that they'd come up with literal _theories_, theory being something you wish to prove as true, instead of just share a vision. So much so that there had developed a freakin' religion over a character from a book series.
I mean, why?

Believe you me, I've been a HUUUUUGE and passionate fan of The Lion King all the way from 1994 when I was a little kid but I never cared about that character much. After all, it's barely even a character, appeared in the movie for some 10 seconds, never spoke a word, was never named or spoken of in any way and never did anything. In the movie, I mean. And wasn't named or given a gender even on the commentary track in 1995. Which existence I never knew about before I grew up and bought the 10th anniversary DVD because I only had the VHS until then and none of my friends had the laserdisc either, but...
I guess to me it was even then apparent that they'd left it up to the viewer's imagination and I cared only about the story and especially about SImba's character.

I mean, even though I did read a few TLK books where it was refered to as a son, I never paid much attention or specifically thought of it as a son. I simply enjoyed the books and casette books for what they were and enjoyed the movie for what it was. I never had any need to try and link them together. I may have of course, already then noticed that there were so many different book adaptations of the movie and come to conclusion that they probably aren't meant to be any absolute truth about anything, even if I didn't yet know that they weren't even written by Disney's own people but by third-parties.
Even when reading the books I cared for and enjoyed the different ways the story was told and the interesting new stories than about what they made of the 10-second almost-character at the end. :)

It appears to be a boy with a small hair tuft. Also Kiara is Simba and Nala's only girl. Her presentation was different. It's possible to be Kopa/book series. Or Kiara/TLK2 & TLK2 or Kion/The Lion Guard.