I usually start off a review with a brief summary of the beginning of my own, however the above blurb basically tells you the plot of the entire book so I thought it would be silly to write another one. I was really excited about this book because, well, a government issue tattoo implicating a girl is ready for sex seems like a topic that could be really well done and so I was definitely intrigued. Nina and her best friend Sandy are both 15 but couldn't be more opposite: Sandy is a typical pre-sex-teen who likes to fluff herself to get the attention of all the guys even though she wants to join the FeLS (Female Liaison Specialists) which requires you to be a virgin; Nina's mom is a free thinker and has enrolled Nina in artistic classes rather than FeLS prep and has bought out Nina's mandatory FeLS contract so that Nina can pursue art if she chooses.The thing that got me the most is that we are never really told why sixteen is such an important age for girls nor why their sexuality is relevant in any way to society. Neither are we told why girls who have this tattoo are considered fair game for any male who wants to have sex with them other than that Nina's society is clearly male dominated which raised all sorts of bells in my head. In circumstances like this I'd like to know more background information on why society developed this way and why females are treated like this. Sequels and a spin-off are planned so perhaps these topics will be covered in them.Nina and her friends spent a lot of time running. More information about what FeLs is mentioned, but in passing, almost as if it were cursory information and not something the reader (or Nina, for that matter) would want to know. I'm hoping there will be more information revealed in subsequent books but as is XVI was a book that I expected to like more than I did.