MEXICO CITY (AP) _ A Nobel laureate from MIT, a nun from Indonesia and a broadcaster from Chicago, all Mexicans by birth, regained their original nationality on Thursday without sacrificing their foreign citizenship.

In a ceremony at the National Palace, President Ernesto Zedillo presented the first 12 certificates of nationality under a law approved in March that allows people to hold citizenship abroad without losing Mexican nationality.

``Mexicans: Welcome to your country,'' Zedillo told more than 100 people gathered for the ceremony. ``For many Mexicans abroad, this was the dream that for many years seemed impossible.''

All Mexicans who have given up their citizenship, including the millions who have become Americans, are now eligible to regain their Mexican nationality. That's akin to citizenship, except for regaining voting rights and some other privileges and duties.

First in line was Mario Molina of the Massachusetts Institute of Technology. He had expressed a dream of recovering his Mexican nationality in his speech accepting the 1995 Nobel Prize for chemistry.

``Promise fulfilled, Dr. Molina,'' said Zedillo as he handed over the document.

Molina expressed ``great satisfaction'' at once again holding nationality of ``this native land that gave me so much.'' He promised to set up a team to study ways of solving Mexico City's smog problems.

``I'm a ball of nerves,'' Jose E. Chapa, a pioneer Spanish-language broadcaster from Chicago, told reporters before the ceremony.

As he took the certificate from Zedillo, he said that regaining Mexican nationality ``is like being born again.''

Chapa, 78, moved to the United States 45 years ago but took U.S. citizenship only nine years ago because he was encouraging Latino citizens to vote _ and thought he should do so as well.

``Many Mexicans say, `I will not become a U.S. citizen in order to not betray Mexico,''' he said. ``Now they have a free conscience.''

Some Mexican officials said during debate on the measure that it would eliminate concerns of longtime U.S. residents, so they could take up citizenship and participate in politics in the United States.

The law eliminates the loss of Mexican inheritance and property rights that previously faced those taking foreign citizenship.

However, nationals who are not citizens cannot vote, serve in the armed forces, hold most public offices or work aboard Mexican-flagged ships or airlines.

Foreign Secretary Rosario Green said that through May 31, the government received 3,738 nationality applications, the large majority filed in the United States.

Among those receiving certificates Thursday were Allan Olvera Rivero, who slept at the door of the Foreign Secretariat in order to become the first person to apply, Indonesian nun Celina Gomez Villarruel and Margie A. Emmarman, an adviser to Arizona Gov. Jane Hull.