Not just vaccinations there; although that probably accounts for many of them. There's also those whose mothers may have smoked and drank through their pregnancy, or even just consumed a lot of processed foods, which may result in deformation and learning disabilities in children, but a lot of research on the connection between the diet of pregnant mothers and children born retarded or lame is non-existent because the very people who could afford to do the non-biased, third-party studies are the very people who do not want those studies conducted in the first place.