As much as X-Men is an action/adventure/drama, it showcases many social/political issues our society faces today. It's abundantly clear that society perpetuates a certain image to its members and in response, X-Men: First Class permeates a message regarding differences crossing cultural and social borders. As outcasts, social anomalies, and outliers of society, these mutants are ridiculed because they don't fit into the bevy of the norm. They have been classified as "homosuperior" because of their uncanny abilities to do certain things like telepathy, telekinesis, shape shifting, teleportation, etc, which are sometimes matched with physical characteristics that set them apart from homosapiens, making them feared and misunderstood.
Mystique invariably hints throughout the film that her natural physical form (as seen above) prevents her from accepting who she is. Her blood red hair, yellow piercing eyes, and blue scale covered skin unequivocally make her stand out. However, her mutant gene allows her to shape shift into any physical form she desires. She disguises herself as a white blonde girl with curly hair, an image that society obviously favors the most and hankers to make more ubiquitous in physical appearance.
Hank tells Mystique that people will only accept her as a white girl with blonde hair and not the way she was born, covered in blue scales. Her yearning to be "normal" drives her temptation to inject an experimental drug that will make her "human" state permanent. However, she discovers that she will have to fight for her identity and that society will have to adapt to her, and not the other way around.
Although someone who feels unaccepted may not have blue scales, claws coming out of their fists, or look like the Hulk (although you may never know!), they are still fighting the same battle for equality and acceptance that these mutants are fighting for. The message delivered by the movies and comics, nourished with ample amounts of fantasy, is powerful and a sanctuary for many kids who feel misunderstood.
So: GO SEE X-MEN: FIRST CLASS
X MARKS THE (G)SPOT.