There's plenty of sex-related material in The Catcher in the Rye, but there just isn’t a ton of actual sex. (Sorry.) Holden just isn't ready to go there, probably because sex is one of the dividing lines between being a child and an adult. Not only that, he has some nasty associations with sex—like molestation and abuse. We never get a straight-up statement about what happened with Jane and his stepfather, or Holden and any of the apparently “twenty” or more “perverts” who came on to him, but we can tell that something unpleasant is going on.
In fact, it seems to us that being a kid is no protection—despite what Holden thinks.