A year and a half ago, Bernard Siegel was a Coral Gables personal injury lawyer. Two weeks ago, he masterminded a worldwide conference on cloning and stem cell research at the United Nations.

How did Siegel go from Coral Gables to the U.N. in 18 months?

The Raelians did it.

You remember the Raelians -- the group that believes aliens used DNA to create life on Earth. A few years back, a company launched by the Raelians' founder -- Clonaid -- announced at a Hollywood press conference the birth of the world's first cloned baby. After the story made headlines around the world, Siegel filed a lawsuit asking the Broward Circuit Court to look into the baby's welfare.

''I used to do a lot of child advocacy work,'' said Siegel, who is married and has two grown children. ``This alleged child was nothing more than a typical milk-carton child being manipulated or exploited.''

SCIENTIFIC CONCERN

The baby never turned up, and many experts concluded the story was a hoax. But during the legal proceedings Siegel heard from several scientists. Their concern: No one was educating the public about the difference between reproductive cloning, which would create cloned people, and therapeutic cloning, which is tied to stem-cell research and could lead to breakthroughs in diabetes, Parkinson's and paralysis, among other conditions.

So Siegel left his 30-year law career last year to found a Miami-based nonprofit, the Genetics Policy Institute. His mission: Convince key policymakers that reproductive cloning should be banned, but therapeutic cloning and stem cell research should be actively supported.

`CLARITY OF PURPOSE'

''There was a vacuum and I just happened to have the clarity of purpose and the drive to do something,'' Siegel said.

And the constitution to withstand a political firestorm. With President Bush's policy limiting stem cell research under attack by some members of Congress, Nancy Reagan's recent public support of stem-cell work and a pending $3 billion initiative to fund stem-cell research in California, Siegel has found himself at the center of one of the hottest subjects in medical research.

''He's emerging as one of the national leaders on this issue, recognized by top scientists who traveled across the oceans to come to his meeting in New York,'' said Daniel Perry, president of the Coalition for the Advancement of Medical Research, which lobbies for stem cell research.

The U.N. meeting focused on the difference between reproductive and therapeutic cloning.

Scientists have demonstrated it's possible to take the DNA, or genetic code, from an adult and insert it into an unfertilized egg. Theoretically, this cell could be implanted into a woman's uterus and grow into a cloned individual. This would be reproductive cloning.

In therapeutic cloning, the egg is injected with DNA from an adult, but it is never implanted in a woman's uterus. Instead, the egg grows in a lab into a cell cluster that includes embryonic stem cells, which can transform themselves into virtually any type of cell or tissue. Scientists say these new cells could lead to treatments for many major diseases.

In recent years, many of the world's leading scientific associations have come out opposing reproductive cloning but supporting therapeutic cloning.

RELIGIOUS GROUPS

But some religious groups, including the Catholic Church, oppose all forms of cloning. The church believes that a human embryo is created the moment the adult DNA is injected into the egg cell, according to Rev. Alfred Cioffi, a Miami-based priest with a Ph.d in bioethics.

''When we obtain human embryonic stem cells, we are destroying embryos,'' Cioffi said.

Because of concerns like these, a U.N. proposal to ban all forms of cloning came within one vote of passing a key committee last fall. That prompted Siegel to take his message to the New York institution.

He worked with legal advisors from several Asian delegations to bring scientists from around the world to speak there earlier this month. Delegates from about 60 nations turned out to hear the scientists, according to Marc Pecsteen, who attended as a Belgian delegate.

Siegel ''practically is the person who alone put together this effort . . . one person at a time, one scientist at a time, one organization at a time,'' said Camillo Ricordi, a University of Miami diabetes researcher who serves on Siegel's advisory board and who spoke at the conference. ``He's an incredibly driven advocate.''

PENDING AT U.N.

The U.N. is slated to take up the cloning ban again this fall. Pecsteen, whose delegation supports banning reproductive cloning but believes countries should decide whether to ban therapeutic cloning, said it is impossible to say whether the conference changed the views of any delegates. But he welcomed the input from the scientists.

''Last year there were many pro-life groups advocating a total ban who were very active in the corridors of the meeting rooms distributing papers, and there was nothing from the side of the scientists,'' Pecsteen said. ``This is the first time the scientific community has come forward with their views. In a way it creates a new balance.''

Siegel, who called the U.N. conference ''the greatest achievement of my professional life,'' remains the sole employee of the Genetics Policy Institute. But he has grand ambitions.

''I'm building a global constituency,'' he said. ``We are going to be a voice well into the 21st century.''

Jacob Goldstein is The Herald's new medical writer.