Within a database of 42,232 children that was compiled by an identity-protection business, 4,311 -- 10.2% -- had someone else using their Social numbers, according to "Child Identity Theft," a report by Richard Power, a distinguished fellow at Carnegie Mellon Cylab.

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In one case, a 17-year-old girl's Social Security number was used by eight different people to amass $725,000 in debt. In another case, a 14-year-old boy had a 10-year-old credit history that included a mortgage on a $605,000 house, according to information supplied to Power by the identity-protection firm All Clear ID.

The study analyzed the types of documents on which the Social Security numbers appeared, and it found that 70% were loan or credit card , 18% utility bills, 5% property assessments, deeds, mortgages and foreclosures, 4% driver's licenses and 2% vehicle registration.

While 1 in 10 children in the database had their identities stolen, only 0.2% of the adults fell victim in the same way, Power says, and that stark contrast raises questions. "Are child Social Security numbers a hot commodity?" Power writes. "Are cyber criminals and other fraudsters seeking them out? Are child IDs preferable for fraudsters?"