Actually, it's mostly the USA, where age of consent is 18 in many states and at the federal level. In the rest of the world, teens can legally fuck :)

Hmm, the federal law might actually apply in this case as it's a text that presumably crosses state lines. However, I grew up in a state where I could legally have sex at 16; even then there were romeo and juliet laws that would allow sex with an older individual if they are close in age. It's a little crazy to find that you can have sex but not over the phone.