Guatemalan legislators approved a new law Tuesday to tighten adoptions, while allowing pending adoptions — mostly to U.S. couples — to go through without meeting the stricter requirements.

The legislation had upset thousands of would-be parents who had invested their savings to adopt a child from Guatemala, which is second only to China in sending adoptive children to the United States. Many feared thousands of children would be left in limbo.

However, the law approved by Congress stipulates that pending adoptions, some 3,700 children already matched with prospective parents, will be allowed to move forward without being subject to the new rules.

The law, aimed at cleaning up an adoption process that critics say allows birth mothers to sell their babies, will take effect next year. It requires the signature of President Oscar Berger.

"Starting Dec. 31, the business of adoptions is over," said lawmaker Rolando Morales, one of the measure's biggest supporters.

Adoptions in Guatemala are now handled exclusively by notaries who work with birth mothers, determine if babies were surrendered willingly, hire foster mothers and handle all the paperwork.

Notaries charge an average of $30,000 for children delivered in about nine months — record time for international adoptions. The process is so quick that one in every 100 Guatemalan children now grow up as an adopted American; Guatemala sent 4,135 children to the U.S. last year.