(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.
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.