The impetus for the campaign can be traced back to a crime spree in the northern Chinese region of Inner Mongolia. For nearly three decades, the police there investigated the rapes and murders of 11 women and girls, one as young as 8. They collected 230,000 fingerprints and sifted through more than 100,000 DNA samples. They offered a $28,000 reward.
Then, in 2016, they arrested a man on unrelated bribery charges, according to the state news media. Analyzing his genes, they found he was related to a person who had left his DNA at the site of the 2005 killing of one of the women. That person, Gao Chengyong, confessed to the crimes and was later executed.
Mr. Gao’s capture spurred the state media to call for the creation of a national database of male DNA. The police in Henan Province showed it was possible, after amassing samples from 5.3 million men, or roughly 10 percent of the province’s male population, between 2014 and 2016. In November 2017, the Ministry of Public Security, which controls the police, unveiled plans for a national database.
China already holds the world’s largest trove of genetic material, totaling 80 million profiles, according to state media. But earlier DNA gathering efforts were often more focused. Officials targeted criminal suspects or groups they considered potentially destabilizing, like migrant workers in certain neighborhoods. The police have also gathered DNA from ethnic minority groups like the Uighurs as a way to tighten the Communist Party’s control over them.
The effort to compile a national male database broadens those efforts, said Emile Dirks, an author of the report from the Australian institute and a Ph.D. candidate in the department of political science at the University of Toronto. “We are seeing the expansion of those models to the rest of China in an aggressive way that I don’t think we’ve seen before,” Mr. Dirks said.
In the report released by the Australian institute, it estimated that the authorities aimed to collect DNA samples from 35 million to 70 million men and boys, or roughly 5 percent to 10 percent of China’s male population. They do not need to sample every male, because one person’s DNA sample can unlock the genetic identity of male relatives.