Legislation has been introduced in Congress to create the National Voluntary Mutual Reunion Registry, to assist adopted siblings to locate one another. Observers say the concept is potentially controversial due to two concerns: that it would invade privacy, and that it would duplicate private and state efforts.

• Although no one knows for sure how many adoptees there are in the United States, best estimates put the number at about six million.

• Between 15 percent and 25 percent of adoptees and birth parents are believed to search for family members at some point in their lives.

• Twenty-eight states now run their own registries, and 11 other states offer alternative search options such as talking to a "confidential intermediary" who can search records for someone.

• A national registry would collect notarized data filed by adult adoptees, birth parents and birth siblings from all states -- and notify registered parties when the information matched.

Some adoptees suggest that Congress help searchers by publicizing the nonprofit, volunteer-run International Soundex Reunion Registry, founded in 1975 and located in Carson City, Nev. Registry officials say the number of people listed is "in the six figures" and more than 1,000 new applications are processed each month. In 1997, the ISRR had 603 confirmed matches.