Does classical music enhance intelligence in children more than other genres?
A great overview of this topic is available in Chapter 6 of the book The Invisible Gorilla by Chabris &amp; Simons. My answer is based, in large part, on their summary of the topic.

The "Mozart Effect" was originally reported by Rauscher, Shaw, &amp; Ky (1993). In the experiment, college students completed a set of typical IQ tests. Before taking the tests, the participants were randomly assigned to either (1) listen to 10 minutes of Mozart, (2) listen to 10 minutes of relaxation instructions, or (3) sit in silence for 10 minutes. They reported that participants who listened to Mozart scored an average of 8-9 IQ points higher on the tests than the other groups.

The effect turns out to be difficult to replicate. This is nicely summarized in the introduction of Steele, Bass, &amp; Crook (1999), who also conducted a replication of the original design and found no evidence of a Mozart effect.

Your question is specifically about classical versus other kinds of music, and this is indeed a topic that has been researched as a follow-up to the Mozart Effect. One theory that arose to explain the Mozart Effect (even though the effect itself may not be all that reliable!) is that it has nothing to do with classical music in particular. Rather, the effect is simply about arousal and mood. Listening to music may not increase your intelligence, but it might make you more alert and engaged than sitting in silence or listening to a relaxation script. Schellenberg &amp; Hallam (2006) reported a study in which participants (8,000 British school children!) listened to either (1) a Mozart string quintet, (2) three pop songs, or (3) a discussion about a science experiment. The children who listened to the pop songs performed significantly better than the others, and there was no benefit of Mozart over the science discussion. Nantais &amp; Schellenberg (1999) demonstrated that there was no overall difference between listening to Mozart or an excerpt from a Stephen King story, but participants did tend to do better if they got to listen to the thing they preferred! One explanation, then, is that listening to something you like before taking an IQ test increases your performance (or, conversely, listening to something you don't like decreases performance).