Kay Ann Johnson, an Asian studies scholar whose adoption of an infant girl from China led her to spend years researching the impact of the country’s one-child policy on rural families, died on Aug. 14 at a hospital in Hyannis, Mass . She was 73 .

Her husband, Bill Grohmann , said the cause was complications of metastatic breast cancer.

Professor Johnson, who taught at Hampshire College in Amherst, Mass., was working on an oral history of a village in North China in 1991 when she adopted a three-month-old girl, Tang Li (who became known as LiLi), from an orphanage in Wuhan, a large city in Hubei Province in Central China. She and Mr. Grohmann already had a biological son .

China was more than a decade into enforcing its one-child policy, a draconian effort by the Communist government to curb the country’s population growth. The rule required families to make painful decisions about whether or not to keep their children.

They would pay stiff fines to keep children born “out of plan”; hide them from authorities; abandon or relinquish them; or find friends and relatives who could surreptitiously adopt the m . In a culture that generally values boys over girls, those decisions were even more complicated for families when the child was a girl.