The teen birth rate has been dropping, and things usually attributed to youthful indiscretion like drugs and alcohol just aren't as popular anymore. The entire Hollywood set of tropes popular in 00's teen movies aren't really true anymore.
My point is that social mores in the US are moving faster than current laws. I'm also not really sure whether teenage sexuality is a hard biological reality as, well, social pressures have an ability to change minds. Years ago, 13 year olds were expected to take up work on the farm. Today, 13 year olds are children most definitely. Perhaps there are limits to how much social conditions can condition individuals but at the very least, the whole changing definitions of childhood (or what was called "adolescence" for teens being pushed into the early 20's) is happening and whether it's conditioning or not.
