I think you mean: XMen (2000)
When Magneto is pulled from his parents in the concentration camp, he uses his powers to bend the gates.

http://en.wikipedia.org/wiki/X-Men_(film)


In 1944, a young Erik Lensherr (Magneto) is with his mother and father at a Nazi concentration camp in German-occupied Poland, where they are forcibly separated. He tries to run to them but is restrained. It is here that his superpower manifests itself; in his panic, he severely twists the gate separating them before he is knocked unconscious.