Another study, the International Cohort Study of Mobile Phone Users (COSMOS), might help determine what, if any, future research is needed. COSMOS will be monitoring some 250,000 Europeans over the next 20 to 30 years, looking at potential links between cellphones and brain tumors as well as EHS-like symptoms such as headaches, sleep disorders, and neurological and cerebro-vascular diseases. But results are not due until 2029 at the earliest, and between now and then, the technology will change and proliferate in ways we cannot predict. A study under way at the IIT Research Institute in Chicago, examining the effects of EMF exposure on rats and mice over several generations, should also provide important evidence. A similar experiment, in which mice were exposed to cellphone EMFs 24/7 across four generations, found no harmful effects on the animals' fertility or development. "If [the IIT Research Institute in Chicago study] doesn't find an effect, then we're unlikely to find anything at all," Repacholi predicts.