Arti,
Brian Wilson / Beach Boys: we're quite certain it's a "no". Plenty is known about the instrument they used, which is known as a "Tannerin" today. (A similar instrument is presently manufactured under the name "Persephone".) Actually, if you can find the old movie of what we would today call the "music video" the beach boys originally made for the song, you can even see, superimposed in the background, a finger sliding around on the instrument during parts of the song.
Star Trek: It's singers, not a Theremin. You see, the song had lyrics other than "oooo", and since it was performed with singers, the studio had to pay the royalty to the lyricist even though the lyrics weren't used. The lyricist was Gene Roddenberry. The song has been performed on the Theremin (by Robby Virus and by Armen Ra), but not on any of the soundtracks of the Star Trek television shows or films.
The Simpsons, I'm not sure if we've resolved what that one is with certainty (anyone? anyone? bueller? bueller?) but I believe the producers have expressed their interest in someday learning the Theremin and that they wish they could have a real Theremin, so we're fairly sure it's not a Theremin.
And if you know about Doctor Who, you know it's not a Theremin, right? The song was originally put together by manually splicing together bits of tape of recorded tones, and later versions were performed on a synthesizer.
If your son wants to mention uses of the Theremin in media, the best examples are probably Alfred Hitchcock's Spellbound, and Robert Wise's The Day The Earth Stood Still. If you want more contemporary examples, three contemporary movies I can say with certainty used real Theremin are Ed Wood (Theremin by Lydia Kavina), Hellboy (Theremin by Robby Virus), and Monster House (Theremin by Charles Richard Lester).
What design have you and your son selected for him to build, that he has to gather components for? You do know there are several kits on the market, right? I'm all for the patience-building exercise of selecting an unusual design and collecting the parts and then putting it together, but I just want to make sure you know you can also buy a kit for about $80 and it'll include everything but the soldering iron. See my Theremin web pages (http://theremin.tomfarrell.org/) for details. Should you do the Silicon Chip / Jaycar original design, please make certain to contact me so I can give you some additional info on making it a better instrument.