Actually, no, it's not typical.
There are 24 states where the state provides the age of the victim or age of the offender at time of conviction or commission of the crime. In a detailed analysis I found that less than 1/2% of all offenders were age bracketed where they could have been in a Romeo and Juliet situation. It is a red herring that is often used by critics to blast the value of sex offender registration.
For every story I hear about a Romeo and Juliet I can tell you about 20 sick twisted freaks (to quote Glenn Beck). I had a sex offender's wife contact me once and accuse us of ruining her life because her husband had sex with a 15 year old when he was 16. When we reviewed his conviction history the truth was that he was 37 when he raped a 6 year old. Turns out that this offender, In his mid 50s, had been raping this woman's daughters for years. Or the woman that found out that her new step son was a registered sex offender because he raped his father's second wife's preteen daughters. This woman had twin 10 year olds. The (ex) husband never told here what his son had done. She found out because she found the 17 year old on a sex offender registry.
No sex offender is ever going to tell you that they want to have sex with your kids, even though they do.
Definitely not making a stand on this one, I just find that some of the laws go too far, and I see a difference between the different types of crimes.