Could Christ Have Sinned?

In my Christian Doctrine class we have been talking about humanity as of lately and what it means to be human. Which lead into the the Humanity of Christ. It led into the question: "was Christ able to sin?" I'm not going to try to respond to that question, it's actually the wrong question a more appropriate one is why didn't he? The reason at least that Christ did not sin was this: 

Our desire to please God over ourselves is constantly in limbo. Jesus' desire was always to please the father over pleasing himself.

When will our desire shift to constantly wanting to please the Father?