"Nazi Twins" a Myth: Mengele Not Behind Brazil Boom?

For the initial phase of their study-which has not yet been published or reviewed by outside scientists-the team combed through baptismal records, which the researchers say should cover about 75 percent of the children born in predominantly Catholic Candido Godoi. The records would reveal where and when the town's many twin births had occurred.

The town's baptismal records date back to 1927, long before Mengele's supposed arrival-and so does the exceptional rate of twinning, the team discovered.

Furthermore, the records show no "surge" in twinning in the 1960s, when Mengele is said to have experimented on the local populace, the study says.

Also, the high rate of twin births continues today, which rules out a role for Mengele, the researchers say.

Had Mengele injected mothers with something to alter their pregnancies, the twin rate should have dropped off when his supposed work stopped.

"Even if Mengele had ovulation induction drugs available, they would have had an effect only on the immediate recipients for one generation," said Gary Steinman, a twinning expert at Long Island Jewish Medical Center.

"It was not even known to anyone what the genetic code was at that time, let alone the ability to alter genes, which would have been necessary to carry over the twinning trait to future generations."

Steinman was not part of the Brazilian team's initial research, but he's now helping them search for genetic clues to the phenomenon.

If Not Mengele, Who?

One clue in the baptismal records may hold the real key to Candido Godoi's twins.

The greatest incidence of twinning, by far, is in the Linha Sao Pedro district, some 6 miles (10 kilometers) from the town center, the researchers found.

The neighborhood was settled in the early 20th century by just eight families. Today Linha S?o Pedro's 80 households are home to 44 pairs of twins.

The community's isolation and small size suggests an evolutionary origin for Linha Sao Pedro's outsize twin population. If a small group settles a region and the settlement remains isolated for generations, the original settlers' biological quirks tend to be passed down as the same families intermarry over and over-scientists call it the founder effect.

"By chance, one or two members of these families that started Linha S?o Pedro could have a genetic of predisposition to have twin births," Schuler-Faccini speculated.

Scientists aren't sure exactly which gene or genes are responsible for human twinning, but twin hot spots like Candido Godoi give researchers a chance to search for repeated clues in twin DNA.

Steinman, of Long Island Jewish Medical Center, suspects a role for a growth hormone-produced protein called IGF, which he's previously linked to twinning in both cows and humans. He hopes to discover whether Candido Godoi twins have high levels of IGF and, if so, whether there's a gene mutation responsible for high concentrations of the supposed twin-producing hormone.

Whatever the causes, the town's profusion of fraternal twins isn't even especially rare, said twinning expert Bruno Reversade, of the Institute of Medical Biology in Singapore, who is not involved in the Candido Godoi research.

"There are in Nigeria and Romania isolated villages like this one, but they have not gotten [or] sought publicity," said Reversade, who called the Mengele hypothesis "preposterous."

"I concur with the authors' conclusions that it may be a founder effect," he added.

Twins Spurred by Something in the Air?

Another theory suggests that environmental factors may be at least partly responsible for Candido Godi's profusion of twins.

Locals have long suspected that something-perhaps a pesticide-in the town's water, food, or air may be boosting the twin birth rate, according to the Nazi Mystery documentary.

"We know that twinning can be related to environmental conditions," study leader Schuler-Faccini told National Geographic News. "For example, some studies suggest that women who [consume] more milk and dairy products are more predisposed to have twins."

One explanation doesn't preclude the other, she said. Candido Godoi's twins may be born of some combination of genetics and environmental factors.

But Camarasa, the historian, still believes Mengele may have played some role.

"There is still no convincing scientific explanation of the phenomenon," he said. "There are only hypotheses, and mine is one of them.

"I think that Mengele's life in exile still holds many secrets."

(Edit:Ruby)