Trouble in Paradise

I thought this was a very good addition to the Replica series. Other than the fact that in "Happy Birthday, Amy" amy was transformed into some one older than 13. I assume that this would have happened to all of the other girls as well, seeing as all of them had the same genes. What bothered me was that in Trouble in Paradise, the other girls still appeared to be 13 years old, and I doubt that all of them were shot by a laser gun (at least I think that's what it was) and the gene was removed. I thought this was a bad example of using a character's past history to make a book more interesting.