A German hacking ring called Chaos Computer Club seems to have cracked Apple's TouchID and reports that the main difference in Apple's approach to fingerprint recognition is purely in high resolution. It is possible fool the sensor using a latex replica, which potentially means thieves may be able to lift a fingerprint off the phone itself to bypass security. It may also call into question Apple's claim of 'sub epidermal' scanning which was another one of their claims regarding the scanner (maybe dead fingers will work? eww...).
Interesting note in the article hypothesizes that police or other individuals can more readily force you to unlock your phone than if you had a password or other security. This technique remains to be verified but if genuine, I'm kinda stunned that this pretty old school way of bypassing fingerprint scanners worked.
Primary source;
http://www.dailytech.com/IPhone+Fing...ticle33427.htm
edit; Additional articles;
http://www.tomsguide.com/us/iphone-t...ews-17586.html
http://www.theinquirer.net/inquirer/...pples-touch-id
http://www.bbc.co.uk/news/technology-24203929
http://www.pcworld.com/article/20492...-security.html
http://techcrunch.com/2013/09/22/hac...d-fingerprint/