Does usage of cellphone causes tumour?

No strong evidence: The studies out there show that there could be some risk of cell phone and development of glioma , but the evidence is not strong enough to confirm the link, and needs to be researched further. It is definitely raise a concern, but there is no conclusive relationship. So, use an ear piece and don't let / limit your children use cell phone.

Probably not: There has not been clear documentation of this. This kind of relationship is difficult to prove because there are so many variables that can affect the results. For example, what brand of phone, what about bluetooth headsets, how many hours are you using the phone, how do you hold the phone, how many phones have you used? These are just a few of the considerations.

I say no: This has been a hoopla for two decades despite the fact that it makes no sense biologically. The things that really and truly cause cancer mutate genes (nobody's shown a cell phone does this, and the idea is silly) or greatly injury tissue (which cell phones obviously don't). Studies based on what people report actually beg for false "findings". I'd ignore the whole thing.