The Smithsonian National Zoo has confirmed that its six-week old giant panda is a male. Panda-keepers showed a painting in blue made by the baby’s father, Tian Tian. Blue is a color culturally linked to baby boys in the United States and many other places. For baby girls, the color is pink.

The giant panda was born August 21. Male and female giant pandas look very similar when young, so the zoo did a genetic test to learn the sex of the newborn. The panda cub does not yet have a name. The zoo usually waits until giant pandas are 100 days old to give them a name.

The baby was born pink and almost hairless. At the time, the zoo said the newborn was about the size of a stick of butter — about 12 centimeters long and weighing 110 grams. Now, he is more black and white in coloring. And he has grown quickly. He measures about 35 centimeters long and weighs about 1.6 kilograms.

After Mei Xiang’s pregnancy was announced in August, internet traffic on the zoo’s popular Panda live video feed increased by 1,200 percent, zoo officials said. When the baby was born about a week later, traffic went so high that the video connection broke for many watchers. Zoo officials had to add bandwidth as a result.

“Something like this is kind of a miracle for us,” National Zoo Director Steve Monfort said at the time. “It lifts the spirits of my team and the whole world.”

For now, the Panda-cam is still the only way the public can see the pandas. The zoo reopened in a limited way on July 24. But the panda house remains closed to visitors.