Somebody's Girl

Martha knows she is adopted, but she's well-loved and popular, at least until her mother gets pregnant and she feels her parents' attention start to shift. Upset and confused, Martha lashes out at-and loses-her friends. She also makes no secret about her annoyance at being forced to do a school project about sturgeon with Chance, a difficult boy whose foster parents are family friends. To add insult to injury, Martha's birth mother announces that she is getting married and moving away.
Now Martha isn't number one in anybody's life. When her mom goes into labor prematurely, Martha realizes that she needs to figure out a way to be a better friend and daughter, and a great sister.