this is a perfect book for young teenagers. if you were trying to devise a formula for writing a perfect book for this age group, you could not have done much better than this. 
 1) mysterious parentage. kids are totally self-absorbed. some never grow out of it, of course, but in younger people, it is more excusable - their internal life makes up the majority of their experience, they are used to being the center of attention and they spend a lot of time thinking about themselves and fantasizing. so having romantic, mysterious origins is the best thing ever - "maybe i am the son/daughter of a god/goddess/russian count, etc..." i still wonder about that, even though it is clear where i came from. 
 2) this book has excellent gender equality, so it appeals to both younger girls and boys. goddesses are just as cool as gods, and their children are equally badass. this is rarely the case in teen adventure lit. (see naruto) 
 3) this makes history class relevant.(or wherever it is that kids learn about those wacky greeks) personifying the gods and goddesses makes them more recognizable and immediate for kids; bringing old litterature aliiiive and all that. and they will definitely learn not to mix up chiron and charon. 
 4) but it is also wonderfully subversive. it is all about polytheism and it makes the point that what we consider mythology today used to be a very real belief system for tons of people. any bright kid is going to make the logical leap to thinking about contemporary religion and how one day, it may well fall under mythology for students of the future, and how any current religious disagreements will be just like poseidon and athena's quarrels. because of this, i am surprised that this series has not been more frequently challenged/banned. oh, i know why, because the people most likely to challenge shit are not themselves capable of making that logical leap; they operate solely on knee-jerk see-a-bad-word reactions. 
 but this book is great - it has fantastic pacing, the characters are incredibly appealing, i like the premise, and i really really like that it is five books only. i will definitely read the rest of these puppies when i get around to it.