Touch screen cell phones are no more or less dangerous than any other cell phone. The danger comes from the magnetic field generated by the high frequency (usually PCS - which is in the microwave range) carrier, and you get that by holding the phone close to your ear while talking. But the relative size (not to mention the strength) of the field generated by the electronics needed for the touchscreen is minimal compared to the carrier frequency, so before you are talking on the phone (i.e. using the touch screen), there is no danger.
Some users of mobile handsets have reported feeling several unspecific symptoms during and after its use; ranging from burning and tingling sensations in the skin of the head and extremities, fatigue, sleep disturbances, dizziness, loss of mental attention, reaction times and memory retentiveness, headaches, malaise, tachycardia (heart palpitations), to disturbances of the digestive system. Reports have noted that all of these symptoms can also be attributed to stress and that current research cannot separate the symptoms from nocebo effects
Avoiding injuries from typing and tapping. The position of your wrist also affects the likelihood of injury from performing multi touch gestures on touchscreens. According to Alan Hedge, director of the Human Factors and Ergonomics Laboratory at Cornell University, the more you dorsiflex your wrist, the greater the chance of injury. But, he adds, most gestures don't require too much force, so you're usually safe as long as you don't bend your wrist excessively or repeat gestures too rapidly.
CAUSES..
1. Cell phone use during pregnancy may cause behavioural problems
2.Cell phone users had an increased risk of malignant gliomas
3. Cell phone use was linked to a higher rate of acoustic neuromas
4. Tumors are more likely to occur on the side of the head that the cell handset is used. One hour of cell phone use per day significantly increases tumor risk after ten years or more.
5. Increases Stress Levels. The high frequency of cell phone use can have negative effects on our stress levels. The constant ringing, vibrating alerts, and reminders can put a cell phone user on edge
6. Sleep disturbances and symptoms of depression
7. Responding to messages at rapid speed can cause pain and inflammation of your joints.
8. Back pain is also common with increased cell phone use, especially if you hold the phone between your neck and shoulders as you multitask. "Long periods of cell phone use cause you to arch your neck and hold your body in a strange posture..
9. Increases Risk Of Eye Vision Problems Staring at your mobile device can cause problems in your vision later in life. Screens on mobile devices tend to be smaller than computer screens, which means you are more likely to squint and strain your eyes while reading messages.
PRECAUTIONS
1. Use hands-free to decrease the radiation to the head
2. Keep the mobile phone away from the body
3. Do not use telephone in a car without an external antenna