Couldn't possibly say... in my opinion a lot of these stories are exaggerated but I have little to base that on. I should expect the danger of mobile phones to be limited compared to, say, smoking, drinking or being obese, so while there may be truth in this I don't think it should be top on your list of things to worry about.
I suspect it is a fringe belief without a great deal of evidence. Cell phones have been used for quite a while now, one would expect to see obvious evidence of an issue were there one. But if concerned feel free to take precautions. After all mobile phones were not considered a nessesity on the past so shouldn't be now.
One case does not constitute a study let alone a connection.
There are no references to any independent sources in the article. Can anyone link to the WHO report it mentions? Why didn't they hyperlink it?
A genuine scientific article would link the sources. At best they will have misrepresented the claim which is why they don't link. At worst they made it up, which is not uncommon in this kind of "article".
The article is designed to sell the RF meters it is ultimately advertising.
It's very complex and there have been a number of studies but beat in mind older US analogue mobile phones generated a lot more power than newer more modern ones and that may have an effect on some studies.
Unless you spend a lot of time with your ear glued to the phone I'd not be too worried.
If I spent many hours a day on a mobile phone I'd probably wear a headset