Dr. Cheng is a pediatrician at Princeton-Plainsboro Teaching Hospital who is considered for a position on Gregory House's team in the episode Unplanned Parenthood. She was portrayed by actress Keiko Agena.
House had assigned Chris Taub with the task of hiring a new female fellow to replace Thirteen after Robert Chase failed with Dr. Kelly Benedict and House fired Eric Foreman's choice, Dr. Christina Fraser. Dr. Cheng was assisting with the case of Kayla, a very sick newborn, and had provided insight during emergency surgery. Taub thought Cheng would be a good choice for the fellowship and asked Foreman and Chase for advice. Given their experiences, they advised Taub that House may just be fooling around with him and to be careful. Taub's strategy became to make House think it was his idea to hire Dr. Cheng.
Taub approached Dr. Cheng about the fellowship and she was interested. She said she was tired dealing with kids and their parents and juggling over a dozen cases at the same time.
Taub talked up Dr. Cheng at several opportunities and passed on his own ideas as Dr. Cheng's. House finally got her in on a differential which led him to the idea that something in transfused blood was making the patient better. He then surreptitiously asked her about a "hypothetical case" where a two-year-old swallows a dime and asked her what do. She suggested if it didn't pass, to go after it with a scope.
Dr. House was suitably impressed enough with Dr. Cheng's performance to let Taub know he would be okay with him hiring her. However, when he went to do so, Dr. Cheng told Dr. Taub that he was acting like a child instead of making a decision and standing up to his boss. She decided not to take the fellowship.