Hai Zi’s twins are both female and are named Miao Miao and Xin Xin! They were named by Shao Qiwei, head of the National Tourism Administration who visited the Ya’an Bi Feng Xia Base of CCRCGP on June 26, 2013. The twins were born in her outdoor enclosure at New Leopard Mountain – Bifengxia.
Source: http://www.chinapanda.org.cn/blog.php?id=1159
Source: http://news.xinhuanet.com/yzyd/travel/20130626/c_116297586.htm