* Rights groups say they may be stolen dictatorship babies
* Battle over siblings' identity has political undertone
* Decision to give DNA sample caused surprise, suspicions
By Helen Popper
BUENOS AIRES, June 24 (Reuters) - The adopted children of one of Argentina's wealthiest women came forward to give blood samples on Friday, hoping to quell suspicions they were stolen as babies from murdered political prisoners during military rule.
A 10-year battle by human rights activists to analyze DNA samples from the Noble Herrera siblings, whose mother owns Argentina's Grupo Clarin (CLA.BA) media empire, has become increasingly politicized in recent years.
Clarin had an acrimonious falling out with center-leftist President Cristina Fernandez in 2008 when its news outlets criticized her handling of an uprising by farmers.
Fernandez has urged the courts to clarify the identity of the Noble Herrera siblings, backing efforts by the rights group the Grandmothers of the Plaza de Mayo to find children born to women held in secret prisons during the 1976-1983 dictatorship.
Announcing their surprise decision to voluntarily submit DNA earlier this month, the siblings said they wanted to put an end to the "harassment and persecution" suffered by themselves and their mother.
Felipe Noble Herrera and his sister Marcela, both in their mid-30s, accuse Fernandez of using them as pawns in her row with their mother's company, something the government denies.
"No one wants to persecute them," Cabinet chief Anibal Fernandez said. "(Their identity) needs to be resolved and the easiest way to do it is with a blood sample, with DNA."
The blood samples from the Noble Herrera siblings will be submitted to a genetic database and compared to DNA taken from the relatives of dictatorship victims.
The timing of the siblings' about-face, four months from a presidential election, has raised some eyebrows in the South American nation.
It could prove embarrassing for Fernandez if the Noble Herreras' DNA does not match samples in the database, because her government has pushed hard for them to be submitted.
The Grandmothers group has identified 102 illegally adopted children so far, although they think there could be several hundred more who are yet to discover their true identities.
Up to 30,000 people were kidnapped and killed during the so-called Dirty War in a state-sponsored crackdown on leftist dissent, according to human rights groups.
Many of the babies, kidnapped with their parents or born to captive mothers, were illegally adopted by military families or friends of the military junta. (Additional reporting by Karina Grazina; Editing by Xavier Briand) (email@example.com; +54 11 4510 2505; Reuters Messaging: firstname.lastname@example.org))