There are many misconceptions about serial killers, and I mean, who can blame them!
This here is a very interesting website that lists common misconceptions about serial killers, just in case you would like to get a little bit more informed:
Something I do want to mention is that although nothing is for sure, but when I was researching about serial killers, I looked into their backgrounds and saw that many of them had very rough childhoods. Charles Manson for example had an alcoholic mother who would sell him for booze. Richard Ramirez witnessed a murder when he was twelve years old. These are just some examples, and it doesn't mean that every abused child will grow up to be a murderer, there are other factors that fall into the nature vs nurture theory. Another thing I would like to add is the connection between killers and animal abuse. It is believed, and many people were warned (including my mom) that children who would kill and/or torture animals would most likely grow up to be serial killers.