Genetic testing has revealed that three young giant pandas born at a US zoo that were thought to be males are actually females.
Hines says the zoo then decided to do DNA testing on Po and on twin cubs Mei Lun and Mei Huan. That revealed those cubs were also females, rather than males.
This is not the first case of mistaken gender for a panda born at Zoo Atlanta. Researchers in China determined in September 2011 that Atlanta-born Mei Lan, who was believed to be female, was actually male.
Ms Hines says gender is difficult to determine in young pandas.