Which Spot? Male Spot? Female Spot? Iguana Spot?

Spot first appeared in "Data's Day" as a male, long-haired Somali cat. (citation needed • edit) According to Richard Arnold, Spot was initially a male Abyssinian cat. The reason the cat's gender was inexplicably changed was, in reality, that Jeri Taylor decided Spot should have kittens. Also, the cat which first portrayed Spot died and was then replaced by a pair of other cats. (Star Trek: Communicator issue 101, p. 15) In subsequent appearances, Spot was seen as a more common American short-hair orange tabby, but still as a male. It was only in the seventh-season episode "Force of Nature" that Spot was first referred to as "she". In "Genesis", she even gave birth. When Spot reappeared as one of Data's memories in "Surrender", Data referred to Spot as "he" again. The Star Trek Encyclopedia (3rd ed., p. 460) jokingly suggests that Spot may be a shapeshifter or the victim of a transporter malfunction. Brent Spiner joked that there were actually 3,500 cats on the Enterprise-D and Data referred to all of them as "Spot". David Arnold suggested that Data perhaps got another cat and simply kept the name. (Star Trek: Communicator issue 101, p. 15)

https://memory-alpha.fandom.com/wiki/Spot

Spot is probably the most confusing character on TNG.