I absolutely adore this album, as with all System of a Down's albums. I have been listening to System since I was about eight years old, as with other "inappropriate" bands/singers. None have encouraged me to curse or do anything "bad". Heck, I'm a fourteen year old girl and I can't recall a time I have lied or cursed, even with listening to music such as this. I know some parents might find System's lyrics distasteful, but hey, from the schools I've been to (public and private), I see fifth graders using worse words and talking about worse things than System does. The music is mostly political, or trying to open the listeners mind to new ideas, or steer them away from the commercialism and lies we face in our world/society. Don't be turned off by B.Y.O.B, it is the only song that is that "extreme" that System made. Any drugs that are in the songs are referred to in negative perspective, describing how they might ruin your life or alter your view on reality. The songs that use the worst language are "Cigaro" and "B.Y.O.B" (C**k, S**t, and f**k), but most teens hear these words daily, and much more of it in rap and hip-hop. The song "Violent Pornography" is basically about how the media portrays society on TV, and showing that the filth you find on TV now a days can be compared to a violent pornography, so if you were thinking this song was about sex, it's not. Much of the lyrics will probably sound like nonsense, but in order to understand all of their songs, you have to decipher the lyrics, so their songs also pose a mental challenge for the listener (that is if they care to know the meaning). The music itself mixes genres, but generally is rock/metal. In my opinion, this isn't their best album, but like all of System's albums, the music is poetic, entrancing, inspirational, eye-opening, VERY unique, political, and better than the usual stuff you hear. System also mixes some crude but funny humor in some of the songs.
To put simply, if you don't want your kid to hear the reality of the world we are now facing, such as the degradation of American society and government, or don't want them listening to metal or a few bad words that they normally hear anyway, don't let them listen to the album. If all that is okay with you (which it should be), then go ahead and let your kid listen.