I think Iowa has a good law. 16 is the age of consent, but there is a "Romeo and Juliet" provision that protects people within 3 years or something like that (a 16-year old kid will not be a sex offender for having sex with his 14-year old girlfriend).
I think 16, but we really need to seriously modernize our laws these issues. Two 14-year-olds sexting each other shouldn't warrant sex offender status. Those laws have gone too far. Sex offender status should be reserved for true sexual predators.
Both of these sound about right. I voted 16.