Here's something I've been wondering about. Why do Marty's parents look just like his great-grandparents in Back to the Future III? Huh? That's just fracking weird. Is it a universal constant that each couple in his ancestry has to look identical? That's just yucky. I mean, what if that's inbreeding on some level. If all the women come from the same stock as well as the men. That must mean Marty's from the south and has genetic problems. Freak.