Isabell Rohde's job is to take care of and play with Yoyo. [Photos Provided by Chongqing Holiday Cultural and Tourism Exchange Center]

There are about 10 agencies who are involved in the au pair program in China and about 700 foreign au pairs came to the country last year, says Ma.

"Thanks to the country's fast growth, an increasing number of young foreigners are applying for positions in China," he says.

The agency has matched 15 Chongqing families with au pairs this year.

"The selection process is mutual," says Ma, adding that the two sides communicate directly via email and video chats to see if they click.

"Almost no foreign au pair can speak Chinese, so Chinese parents need some foreign language skills," he says.

Meanwhile, though an increasing number of Chinese parents are buying into the program, many have concerns about the system.

She Ke, the editor-in-chief of a fashion magazine and a mother of two young children, says: "I cannot imagine having a foreigner living in my home.

"It can lead to lot of cultural and lifestyle conflicts. For instance, do I have to prepare Western food for the au pair every day?"

Zhuang Yilin, a senior manager at a multinational company in Shanghai and also a mother of two, has been thinking about having an au pair for some time.

"It is not easy to find a trustworthy one," she says.

"I want an au pair with a good personality and a positive attitude. I have heard some negative feedback about au pairs in China, so I am being very cautious."

Language experts also say that it is not necessary to have an au pair for kids at very young age.

Liu Jian, Chief Academic Officer of Best Learning, an English language training center, says: "While having a native speaker at home is obviously the best way to pick up a foreign tongue, if the child is only three years old, the au pair is just a babysitter and cannot teach the child a lot. I think the proper age (for a child to have an au pair) is around 10."