Different states have various age of consent laws that govern at which age individuals are lawfully able to consent to engage in sexual activity. Because of the lack of a single federal law that clearly delineates an age, confusion can arise regarding the laws of individual states.
Here in Colorado, the age of consent is 17, meaning that anyone 16 years old or younger can't give consent to have sex. Thus, those participating in sexual activity with those in that age group could be arrested for statutory rape.
If that sounds a bit draconian, rest assured that the state has an exemption for those minors who are close to one another in age. Sometimes referred to as the "Romeo and Juliet law," it protects underage couples from prosecution if they have consensual sex but one (or both) partners have not reached the age of consent.
For example, under Colorado's close-in-age exemption, 16-year-old teens can have sex with individuals who are no more than nine years older than they are. Similarly, minors 14 and younger can have sex with those three or fewer years older.
An additional defense to a charge of statutory rape is that the alleged perpetrator and victim are legally married. In such cases, common law marriages do not apply and will not be a viable defense strategy.
Being arrested on any type of sex charge involving a minor below the age of consent carries heavy criminal penalties. Those facing such situations require vehement defense strategies that take into account all aspects of the relationship between the parties, including use of close-in-age exemptions when possible.
Source: ageofconsent.net, "Colorado Age of Consent Laws 2017," accessed Feb. 15, 2017