Wireless sensitivity

How can it be, that most people use wireless connection to get onto the internet and their mobile phones to call their family and friends and this is completely normal. On the other hand there are a handful of people who feel really ill, when they do exactly the same. What is it, that causes this reaction? It is so difficult to find out, that some doctors do not even recognise this "allergy" to wireless connections as an existing condition. This is exactly the point that makes it so difficult to find a treatment and for the effected people to be respected in society.