Women get their blood pressure measured before entering the chambers for doctors at a Beijing hospital. [Tian Baoxi / For China Daily]

A World Health Organization study in 2010 found 48.5 million couples worldwide unable to have a child after five years of trying to have one.

"China has average infertility when compared with world figures," says Liu Ping, deputy director, Center of Reproductive Medicine, Peking University No 3 Hospital.

The 56-year-old gynecologist was on the team of doctors credited with Zheng's birth in 1988.

In China, from 40 to 50 percent of infertility cases report problems with females, between 30 and 40 percent with males and from 10 to 20 percent with both, she says.

The common fertility issues for women relate to uterine disorders such as endometriosis and polycystic ovarian syndrome, and for men, they are mainly about sperm count, quality and mortality.

Including TCM

Back in Changsha at the Xiangya Hospital of South Central University, a top medical institution in Hunan, the waiting halls are packed with men and women. Among them is a man who works in Shanghai's financial world. He says his sperm count has been falling despite fertility treatments for the past two years.