"It's not surprising that results haven't been consistent," said Daniel Wartenberg, associate professor of epidemiology at the Environmental and Occupational Health Sciences Institute of New Jersey. "If you look back at smoking, solid studies were published on the subject around 1950, yet it wasn't until the mid-60s that the Surgeon General felt there were sufficient data to make a statement on health risks associated with cigarette smoking. By that time, there were probably hundreds of papers on the topic. There are a lot of things we know that have certain health effects, yet we don't understand how they work. We're only beginning to unravel the mysteries of how aspirin works."
In the 1996 report by the National Academy of Sciences, a meta-analysis concluded that, on average, there is an association between childhood leukemia and wire codes (a system developed by Ed Leeper that ranks the size of electrical wire -- an approximate measure of current carrying capacity -- and their distance from one's home.) However, the report does not state that these were causative sources.