Apple products are often hailed with words like 'genius,' 'revolutionary,' or 'game-changing,' but the company's desire to push the envelope has had an unexpected impact on iPhone 4 owners who are left-handed. Unlike previous iPhones, the iPhone 4's antennae are engineered directly into the steel frame of the phone itself. While right-handed users have no problems, left-handed users who cup the phone with their left hand lose 3-4 bars of signal strength. In many cases, this may be enough to terminate a call altogether.
Whether or not your call is dropped appears to depend on just how strong the signal is to begin with. Apple hasn't publicly commented, but the problem appears to effect 3G signals only; WiFi and EDGE are unaffected. Users are encouraged to dry their hands thoroughly, avoid cupping the iPhone with the left hand, hold it above the problematic area, or put the phone inside a protective case. Right-hand users may also have a problem with this issue, depending on how much you use the left-hand for holding the phone while typing with the right.