A majority of the parents of autistics in one recent survey blamed vaccines for their child's illness. Other alleged culprits have included environmental toxins, increased numbers of geriatric parents (because of their crumbling chromosomes), genetic loading (geeks with genes that predispose them to autistic traits marrying one another), and even excessive TV watching, as Greg Easterbrook recently argued in Slate. Since there is no cure for autism, the hypothesized causes have a particularly powerful hold on the imaginations of people with autistic family members. As Susan Sontag once wrote, "Any important disease where causality is murky and for which treatment is ineffectual tends to be awash in significance."