Music has always taking steps through society. As we change so does our music. (or is it the other way around?) For example, it is hard to overlook the fact that people used to be far more conservative.  Beethoven is the greatest

classical writer in history. And if you look at his time period from the late 1700's to the early 1800's you can see the extreme differences from our society today. Children actually obeyed their parents. If they didn't they were ostracized. Rebellion was met with strict punishment and was not tolerated. 

As we move on in History we see people becoming more and more rebellious. I believe one of the main reasons for this is due to adding words to our music. Now we have gradually grown to giving every artist out there the ability to say whatever they want in music. But this was not always the case. What they would say used to be censored. Keeping the conservative mind. But as we evolve our music, so do our morals. Rock jump started this evolution of moral de-solving propaganda. All of the sudden sex and drugs were being thrown out to the public through music. And on top of that influential people in the rock world were being found out for doing drugs and having sex...a lot. So this became cool promoting more rebellion and more drugs. Which as years go by they always come up with new and creative ways to add more sexual and drug orientated topics in music. For example, todays step forward would be rap.