Now, I'll be honest. I have been reading fantasy books since I was a
kid. A lot of vampire genre is totally inappropriate for Christians (many are very erotic) while others are more tame and readable. This is my humble opinion and so I concede that a person has the right to read according to their conscience.
The book Twilight is about a sixteen/seventeen year old girl (Bella Swan) who moves to a small town in Washington where she falls in love with a 100 year old (but 18/19 year old looking) vampire (Edward).
Twilight fits into the "tame" category. It has a sixth grade reading level feel to it (which did not appeal to me) and frankly, I feel that there are themes in the book that can give immature (and possibly mature) teens an unrealistic and very often imitated look at romance. Which frankly made me want to puke all over the book.
For some reason vampire genre,aside from the horror, has become synonymous with romance. This book is no exception. The horror isn't bad but the romance is sickening sweet. To be honest, I would have preferred the horror over the romance. It seems like every time you turn around in the book Bella and Edward are nuzzling each other, smelling each other, half kissing each other, etc... Everyone seems to miss the part about her doing this with a hundred year old guy.
I have not read the other books but have been given the scoop concerning them. With such blatant physical interaction between these two it shouldn't surprise you that the thought of premarital sex comes up in later books. To my understanding Bella and Edward don't engage in premarital sex but each one has their moments of giving in while the other abstains. After they are married there is unnecessary talk about "rough sex" and so on. There is also a bit about Bella falling in love with a werewolf as well but eventually gives her whole heart to Edward.
Here is my two cents. I have an 18 year old daughter who has read them. She is 18 and can read whatever she wants. I have a 13 year old daughter who wants to read them because everyone else is. I am not allowing her to read them for the reasons I stated above. She doesn't need to have her head filled with romantic nonsense between two teenagers that can, and has in many cases, lead to sex.
So I issue a warning to parents. The choice is ultimately up to you, but if you do allow your teens to read these books please read them yourself so you can talk over the issues they present.