For decades, most couples in China were allowed to have just one child. But in some cities, that policy is changing - most recently in Shanghai. The reason: China needs more young people to care for its rapidly rising elderly population.
After 10 years of marriage the Guos would like to have children.
When asked how many children they want, the Guos glance quickly at each other and then give the same answer.
"One or two. One or two, yeah," Guo said. "I think for society, for country, maybe two children is better. But because the family plan was carried out so many years so maybe this plan cannot change at once. But maybe it will last for more than several years, and after that the government will change that plan and so maybe the next generation people would have two children."
But under a policy from the 1970s, they, and most couples in China are allowed to have just one child.
Many population experts, and Chinese couples, say that restriction is outdated. There are signs the government is beginning to agree, with reports of less strict enforcement. And recently the Shanghai government said some couples will be encouraged to have two.
Sophi Li is an educator from Beijing now doing research in public policy at Hong Kong University. She says initially the one-child policy helped manage China's population, which boomed after the People's Republic of China was founded and sanitation and medical care improved. At 1.3 billion, China is the world's most populous country.
But over time, the one-child policy has resulted in a four-to-two-to-one ratio: For every four grandparents there are two parents and one child. Li says that means as China's population ages there are fewer workers and young people to care for the old.
"That would pose a substantial threat to social stability, which has been heavily emphasized by the government," Li said.
James Vere is an assistant professor in the School of Economics at the University of Hong Kong. He says China's aging population poses social, environmental and economic threats to the world's third largest economy.
"If you have one young person supporting three old people or maybe four, as might seem to be the case, then it's just totally unsustainable," Vere said.
To avoid that, the Shanghai government says couples will be urged to have two children if both the husband and wife are themselves only children. The reason: People over 60 make up 22 percent of the city's population, a number that is expected to grow to 34 percent in 2020.
Although Hong Kong is a Chinese territory, Beijing's one-child policy does not apply there.
On a recent Sunday, Hong Kong couple Ringo and Eva Lee took their two sons in strollers to see their uncle. Eva Lee says their mainland relatives would prefer to have two or more children.
"If they are just allowed to have one baby, then actually they have no siblings," Lee said. "Actually they have very few relatives in the future. No aunts. No uncles. Then I think that's not a good thing for them."
Taking a break from strolling with his baby and wife, Peggy, Ray Yim says it is expensive to raise children in Hong Kong and China.
"The government welfare system is not as good as before," Yim said. "You have to spend quite an amount of money on the raising a child because now competition is huge. You can't just put your baby without any education or raise him up like the past."
Beijing says since the 1970s, its family planning policy has prevented more than 250 million births, easing pressure on the country to feed its people.
But the policy has been controversial in a country where family and ancestry are very important. At times, it has been harshly enforced with forced abortions and sterilizations.
Yet despite the recent change in Shanghai, there is no indication that Beijing will totally do away with the one-child policy in the near future.
Li, the public policy researcher, warns that could result in economic and social problems. She thinks the government should end the policy and allow the population to grow at the same pace as its economy.
The United Nations and other organizations estimate that at the current rate China's population will start to shrink around 2030. If that happens, the data suggest, by 2050, almost of the third of the population will be over age 60, and only 48 percent will be of working age.