You people need to stop confusing the movieverse with Earth 616, the comicverse... it is sad you cannot see the difference. Raven Darkholme (as we like to call her even though it is not her name) has NEVER in her life fought actively for mutant rights. No no, don't try and be shocked. What Mystique used to do in those days with the so called "Brotherhood of Evil Mutants" was not to fight for mutant's rights, that was the cover. What she was trying to do was avert the future written in Destiny's Diaries. Every move she made, every fight she instilled, every murder, every lie, was meant to change the events depicted in the diaries, yet the more she tried the more she failed. Mystique is a ruthless, lying villain, who has been lying ever since she fought Ms Marvel all those years ago. Lying is her personality, lying is who she is. It would not be surprising if she was lying about her personality all along.
And about the other thing... should I make a list of mutants who had part of their powers at birth and then developed the rest of them at the proper age? I could start with Nightcrawler you know, seen as he was born looking like that. I could continue with little Franklin Richards, or Nathan Christopher Charles Summers Dayspring, the man now known as Cable.
And about what mightiest mortal says... I think it's nothing of the sort. I was raised in a perfectly happy family, I had the most normal of childhoods possible, the word gay was never even mentioned in my home, yet I turned out gay while my brother who was raised in the same fashion is not. Events in childhood do not shape who you are, YOU shape who you are, YOU choose what to do with your life, not what other people inflict upon you, it is YOUR choices that count, that make you who YOU are, no genes, no life-experiences, just your good old mind.