They visited Xishuangbanna and Pu'er in Yunnan province and avoided crowds at some less visited places. They took the boy to pick up pineapples in Xishuangbanna's Manyuan village, and learned about the coffee planting history in Pu'er, and visited a plantation.

He says compared with before, some domestic destinations have developed new experiences to cater to the needs of visitors. For example, in Xishuangbanna, tourists can take a stroll with an elephant in a tropical forest.

"After several years of traveling, my son likes to communicate with others, and when we travel overseas, he plays with other kids even if he can't speak the local language. He's also broadened his horizon and be mature," Ren says.

In September 2018, they were stuck for about 40 hours in the airport in Osaka, Japan, due to flooding caused by a powerful typhoon. They had to sleep on the ground and the boy didn't make a fuss. When the Chinese embassy sent buses to pick up Chinese tourists, he lined up for several hours and knew the importance of public order.

Some parents, he says, are worried that there will be many problems if they travel with their child, for example, whether the child might have carsickness or airsickness, or won't like the local food.