I used to buy into this more at one time, but this is another dualism that may have a few grains of truth but then gets grossly oversimplified. Very few people would even fit either category perfectly. Conventional wisdom seems to have it that ADD/ADHD people are more right brained and creative and Autistic people are more left brained and scientific minded. I'm not sure where it would leave me, like many on the Autistic spectrum I also have ADD and while I write with my left hand I tend to do everything else with my right. I do appreciate some art but I also watch The Weather Channel. Much of what I used to read about the right/left brain stuff seemed to have a certain bias to it but I can't put my finger on it. It was something on the lines of right-brainers being the creative, empathetic, sensitive, mystical, intuitive minority oppressed by a cold, narrow-minded, nerdy, concrete thinking, boring, and domineering left brain society. Where would right-handed artists and left-handed engineers fit in? I mean many people can lean one way or another and I'm not saying that patterns don't exist, but this has been exaggerated into another "us/them" dichotomy. If anything we need to use both sides to function properly as God gave our brains two hemispheres for a reason.
The following article discusses this and other ideas about the human brain: http://lifehacker.com/5867049/nine-stubborn-brain-myths-that-just-wont-die-debunked-by-science