( CNN ) -- The gender of the cutest cub at the National Zoo is no longer a secret : It 's a girl ! The zoo announced the gender Thursday morning , as well as the paternity of the giant panda cub born last month . The cub is the offspring of Washington 's celebrity panda , Mei Xiang , and the father is Tian Tian , a 16-year-old , 264-pound male who lives in the same zoo , officials said . The giant panda mama gave birth to the cub August 23 , to the excitement of hordes of fans watching it on public panda cams . Watch the zoo 's Panda Cam . The name of the female cub will be announced 100 days after the birth , per Chinese tradition . At birth , the cub -- which was about the size of a stick of butter -- did well and the mother could be seen cradling it in her den at the National Zoo . But the next day , Mei Xiang gave birth to a second cub , which was stillborn . The mama panda groomed the cub for 17 minutes before it fell onto the floor of the den motionless , a zoo spokeswoman said . Mei Xiang was artificially inseminated by sperm from two different pandas , zoo officials said . One was Tian Tian , and the other potential father was Gao Gao , a 20-plus years old , 174-pound giant panda from the San Diego Zoo . Giant pandas are one of the world 's most endangered species .
NEW : The new panda cub is a female . A male panda cub born at the National Zoo in Washington, D.C. on April 22, 2012. The father of the cub born last month is Tian Tian . Giant pandas are one of the world 's most endangered species .