Beijing ? Beijing saw double on Saturday as the Chinese capital opened its first festival for twins, attracting hundreds of siblings — a rare sight in a society where birth control rules limit most urban families to one child.

Pairs of twins in matching cowboy hats, sweaters or scarves mingled, chatted and performed on stage at the government-sponsored event in a Beijing park. A pair of men played a saxophone duet, and younger twins danced and sang.

Participants ranged in age from 69 to a set of 4-month-olds in a double stroller. Organizers said 500 sets of twins, including some from abroad, signed up to attend the four-day festival.

A set of 15-year-old triplets from eastern China also showed up.

“We’re never lonely,” said Wang Yanren, one of the trio of teenage girls, who wore matching blue jackets. “Now with family planning, every family is only supposed to have one child. So we’re lucky.”

A similar festival also was held Saturday in the eastern Chinese city of Hefei, drawing 200 sets of twins who danced, sang and recited poetry, the official Xinhua News Agency reported.

Chinese, who wish newlyweds “double happiness” and entrepreneurs “double fortune,” look on twins as a sign of good luck. A boy-and-girl pair is called a “dragon and phoenix,” a reference to two traditional symbols of prosperity.

These days, parents of twins are considered especially lucky.

Rules imposed two decades ago in hopes of slowing the growth of China’s vast population of 1.3 billion people limit urban couples to one child and those in the countryside to two.

Twins reach up to try to catch confetti at the opening of Beijing's first-ever twins festival on the second day of a weeklong National Day holiday. Hundreds of look-alike siblings turned out for the festival Saturday.

But twins and other multiple births are exempt from heavy fines imposed for additional births.

Hoping to take advantage of that exemption, some Chinese parents try to hide a forbidden extra birth by registering the child with an older sibling as a set of twins.

The Beijing festival was held to coincide with China’s weeklong National Day holiday, which began Friday, said Tan Ying, director of the park where the event was taking place.

Many echoed the sentiment that having a twin means added emotional support in a society of only children — isolated “little emperors” who Chinese officials worry are growing up maladjusted.

“We have a partner. We naturally have a friend to talk to,” said Zhang Juan, who with her sister, Zhang Chan, wore identical red dresses and yellow scarves. They heightened the effect with matching sets of fashionable blond streaks in their hair.

But still, Zheng Yancui and Zheng Yanzhu, a bubbly pair of sisters in their 30s with matching dimples and sweaters, said looking exactly alike can have its drawbacks.

“It’s hard when you’re first meeting a boyfriend,” Zheng Yancui said, as her sister laughed. “It’s really awkward when her new boyfriend looks at me with that look.”