Don't Nuka, Vitani, and Kovu fall into the category of new cubs being born during Scar's reign?
I agree with TheBlackCatCrossing's theories, Regulus's, and ClearGreenWater to an extent. Here are my additional plausible reasons:
1. Scar's cub(s) would have created character(s) too many for the story. Think in terms of an adaptation of the story of the Exodus (which TLK borrows from), what did Pharoah's son do that was crucial to the story? Not a whole lot, when you think about it from Moses's point of view. Unless the character(s) is killed in the film, it would have created "sequel bait" for the next film if Simba decides to banish the character causing the character to desire to have the throne returned back onto Scar's lineage. The filmmakers had no intention of making a sequel due to
Pocahontas being seen as the more successful film of the two.
2. At the beginning of the film, Scar states, "As far as brains go, I got the lion's share, but when it comes to brutal strength, I'm afraid I'm at the shallow end of the gene pool." While it's given as the reason for Scar to not challenge Mufasa, I can interpret the line for the reason for him not to have cubs. Since Scar knows he is weak genetically, I'm pretty he wouldn't want to pass that trait onto his child(ren) especially know that you have battle with other lions in order to retain his power. However, the shared genetic traits of his mate could have made the cub stronger than him, but genetic traits are quite complex to determine the physical outcome of a descendant.
3. Scar could have had a rough childhood, and felt no one really loved him. Scar in the Broadway musical states this, but like BCC states, it should be treated as an alternate universe, not as a canon work. Well, if Scar felt no one really loved him, it hardened his heart to not love anyone in return as if he was some sort of a psychopath. This also ties in to the "antisocial personality disorder", which we see in some ways in the film as Scar not being around with the pride, and a blatant disregard for the rules of the kingdom.
[quote="DGFone"]
Which of course meant that he tried to get his with with Nala, causing her to flee. And Shadowlands was not included in the movie for spoiler reasons and not to "protect the kiddies". After all, the Broadway show went with All of this stuff, and young kids watch that too.[/quote]
Um, I'm pretty sure Scar's seduction of Nala was not included in the movie to "protect the kiddies" because co-director Roger Allers confirms below that the filmmakers felt the scene was overall creepy and another reason was because they felt it dragged on too long.
[youtube]I0WATOVmLtQ[/youtube]
I'm not sure if you're referring to "Shadowland" to the actual song or just the deleted scene. However, I will stand
partially corrected if you show/tell me credible proof that the song/scene was written out for spoiler reasons. If it's in the audio commentary, I'll pick up on it when I listen to it again.
[quote="Remorazz"]Well, we don't know he
didn't have cubs, it's just that they never appeared in the first movie.
Nuka and Vitani have the potential of being his cubs, but we don't really know for sure. I don't think that none of the females 'liking' him would be a strong possibility, as the lions exiled to the Outlands supported Scar.[/quote]
[spoiler]

It's been cleared up a long time ago so we can know for a fact that Nuka and Vitani are not his descendants.[/spoiler]