Su Lin gave birth to twins on August 3, 2014 at the Ya’an Bi Feng Xia Base of CCRCGP.
One cub, weighing 173.8 grams, is male but researchers have not been able to tell the gender of the other as Su Lin has been holding it since it was born.
Su Lin was born in August 2005 at San Diego Zoo in the United States and returned to China in 2010.
Source: http://www.chinapanda.org.cn/blog.php?id=1323
Source: http://www.globalpost.com/dispatch/news/xinhua-news-agency/140804/returnee-giant-panda-delivers-twin-cubs