California passed the first sex offender registration law way back in 1947. These laws became increasingly common beginning in the 1980s, culminating with the federal Jacob Wetterling Act in 1994. Patty Wetterling, who lobbied extensively for this legislation following the death of her son, now condemns sex offender registration laws as overly harsh. But that's the subject of another blog.
In the United States, many people believe that all sex offenders are the same. A boy who's a few months too old to have a consensual relationship with a teenager is just as bad as a man who rapes a nursing home resident. That's just one reason the sex offender registration requirement is a very difficult pill to swallow.