Francisco Madariaga doesn't know when he was born, but he's told his umbilical cord was still attached when he was pulled from his mother in a clandestine detention center and illegally adopted during Argentina's military dictatorship.

Madariaga, now 33, hopes to learn clues to his past when a long-awaited trial begins Monday, the first in which former Argentine leaders are charged with implementing a systematic plan to steal the babies of political prisoners. In all, about 400 infants are believed to have been stolen, perhaps the most horrific of the crimes against humanity that characterized the 1976-1983 dictatorship.

Former dictators Jorge Rafael Videla and Reynaldo Bignone face life sentences if convicted in the kidnapping of 34 children. Also charged are six other former military and police officials.

"It's going to be good to confront them so they see that they couldn't get away with it with everyone, that sometimes the truth comes out," said Madariaga.

The military junta's so-called Process of National Reorganization resulted in the kidnapping, torture and murder of as many as 30,000 political dissidents. But they generally drew a line against killing unborn children — so they kept pregnant detainees alive until they gave birth, before killing the mothers. Their babies were later given to military couples or their allies, who adopted them with falsified paperwork.

"For the first time in Argentina those responsible for the systematic robbery of babies during the dictatorship will be tried," said Alan Iud, a lawyer for the Grandmothers of the Plaza de Mayo human rights group.

Madariaga was the 101st stolen baby to recover his identity with the help of the Grandmothers.

DNA tests showed he was born to Silvia Quintela and Abel Madariaga, members of the Montoneros, a leftist group targeted for elimination by government death squads. Quintela, a 28-year-old surgeon who treated the poor in a Buenos Aires suburb, was kidnapped Jan. 17, 1977, and held in the Campo de Mayo dentention center until she gave birth that July. Then she disappeared.

Francisco's father narrowly escaped into exile, returning only after the dictatorship ended. He then joined the Grandmothers and spent the next three decades looking for his son.

Until a year ago, Francisco had been told he was Alejandro Ramiro Gallo, son of former military intelligence officer Victor Gallo. But he always had doubts, and finally confronted his adoptive mother. She confessed to him, and they went together to the Grandmothers. Victor Gallo was arrested the same day that Francisco and Abel Madariaga met for the first time.

"I lived a lie for 32 years," Francisco Madariaga said. "We're not normal like everyone else — we have problems that most people can't relate to. For example, when someone tells me he lied, but it was just a little white lie, I can't stand it."

The case has taken 14 years to reach trial, and it may take as much as a year to hear testimony from about 370 witnesses in a maximum-security courtroom in the capital. Videla and Bignone already have been sentenced to life terms for other dictatorship-era crimes. Francisco Madariaga wants similar sentences in his case, but says that won't ease his pain.

"The wound will never heal. Everyone in the world has the possibility of burying their loved ones, but I couldn't do it with my mother," he said.