Which phones are most dangerous?

Look at the Specific Absorption Rate (SAR).

An example of the mobile phone emissions limits referred to in research (for example, in our story: Headsets reduce risk of mobile-phone cancer) are those of the the USA's Federal Communications Commission (FCC). These limits are given in terms of a unit referred to as the Specific Absorption Rate (SAR), which is a measure of the amount of radio frequency energy absorbed by the body when using a mobile phone. The FCC limit for public exposure from what the US call cell phones is an SAR level of 1.6 watts per kilogram (1.6 W/kg). The EU limit is higher - an SAR level of 2W/kg. (Proof in itself that this is not an exact science.)

You can see where your phone figures in the SAR tables on the FCC site or here: What is SAR.

iPhone dangerous in the pocket?

It's not always easy to find out how your phone figures in the SAR stakes. You'll search the Apple website in vain for any mention of SAR or specific absorption rate although the US user's manual for the iPhone 3G will tell you all you need to know including the fact that 'iPhone’s SAR measurement may exceed the FCC exposure guidelines for body-worn operation if positioned less than 15 mm (5/8 inch) from the body (e.g. when carrying iPhone in your pocket).'

The iPhone 3G has the highest SAR of the iPhone family (1.38 W/kg). The iPhone 4's SAR is 1.17 W/kg, the iPhone 3GS 0.79 W/kg and the original iPhone 0.974 W/kg.

Also on malehealth:

• Headsets reduce risk of mobile-phone cancer
• Tips for safer mobile phone use