SEOUL • The biggest obstacles to finding more matches are the databases themselves.

There is no single consolidated database widely available both to South Korean birth parents and to overseas South Korean adoptees.

Databases used by Americans and South Koreans are incompatible and cannot share information.

The South Korean police collect DNA samples for their national database of missing people. Adoptees and birth parents are eligible to submit DNA for this database, and many do, but not nearly enough.

The testing done by volunteer group 325Kamra goes into the databases of Family Tree DNA, a Houston-based DNA testing firm, and GEDMatch, a service that scans for genetic matches from three popular testing firms - Family Tree, 23andMe and AncestryDNA.

Ms Kyung Eun Davidson, 33, from Everett, Washington used 23andMe, her birth mother took the test with 325Kamra in South Korea, and they were connected by GEDMatch.

Parents are also a problem. An estimated 1,000 adoptees have submitted their DNA for matching on GEDMatch but only 100 birth parents have taken tests with 325Kamra.

Many are afraid to come forward because of the shame associated with adoption in South Korea, where they risk being shunned by their families and communities.

Also, South Korean laws block adoptees from obtaining their full birth records without the birth parents' consent. And government adoption files are often falsified, incomplete or missing, making birth parents impossible to track down.

From 2012 to last year, less than 15 per cent of adoptees who asked to reunite with their birth parents were able to do so.

NEW YORK TIMES