There are 73.8 million children who are a part of families created through adoption. It's odd that Disney would choose to send a message that adopted children are less part of a family than biological children, but that's exactly what happens in The Avengers.
In one key scene, as the Avengers are assembled they review the evil committed by Loki. Thor confronts the rest of the Avengers because Loki is his brother. When the Avengers list the atrocities he has committed, Thor volunteers that "Loki was adopted". It got quite a laugh from the audience. It implies that an adopted sibling is less family than biological children.
Children don't need to be told they are inferior or defective or less of a family member because they were adopted, especially from someone as trusted as the Walt Disney Company.
The movie was excellent and I don't regret taking my son to see it. I just thought we had moved beyond these stereotypes about adoption.
This is my point of view as the father of an adopted child.
Our family hasn't enjoyed a Disney (non-Pixar) film in years. This one has great story, wonderful characters, and outstanding animation. Walt Disney Feature animation is back! Our son, age 7, loved the movie and was particularly excited that it was a 3-D feature. We saw a sneak preview on 11/15 and the film opens on 11/21
Adnrew Adamson delivered a great adaptation of C.S. Lewis' Prince Caspian. My favorite line is from Aslan: "Nothing ever happens the same way twice." Our family loved the film including our six year old son. Enjoy!