Songfacts®:

• Billy Corgan wrote this song about his younger half-brother Jesse, who has autism and a rare genetic chromosomal disorder. It's part of their second album, Siamese Dream, which broke Smashing Pumpkins with the song "Cherub Rock" and "Today."
• The person speaking at the end is saying, "Now it's, uh, kind of strange, and, uh, kinda hard for me to talk about, but I thought maybe you could help- um, when we start getting physical, rather than having intercourse, he ends up just masturbating himself, and I end up feeling very alienated and unsatisfied, and it's really come between us."
• An alternate version of this song (most commonly seen in the unofficially released collection of rarities Mashed Potatoes) features Pink Floyd-esque slide guitars in the chorus instead of the string section.
• Billy Corgan played a mellotron on "Spaceboy," which adds to the other-worldly feel. A mellotron is a keyboard instrument that plays tape loops - a kind of early sampler. You can hear one on "Strawberry Fields Forever" by The Beatles.
  
  The Pumpkins didn't carry the instrument around with them - it just happened to be in the studio where they were recording. It was producer Butch Vig's idea to use it.
  
  "We were doing 'Spaceboy,' and it really wasn't going anywhere," Corgan told Creem. "Then Butch suggested I give it a go. I did, and after that, I wanted to put it all over everything!"