WBAY - Twins denied driver’s permit because DMV can’t tell them apart - October 23, 2015
"...twins got (drivers license) denied by the DMV, all because a camera could not tell one girl from the other...That computer can recognize faces, a feature that comes in handy if somebody’s is trying to get an illegal ID It apparently is not programmed to detect twins..."
Face recognition failure: Georgia DMV denies twins' permit 'cause computer sees them as one — RT America
Maybe Microsoft Research already has a solution?
Microsoft Tries To Guess Relatives With "Twins or Not" - Slashdot
Are you twins?