The midwife at the 1949 home birth in rural South Carolina delivered a healthy baby girl but didn't file a birth certificate. Donna Jean Suggs grew up, got a Social Security card and found work as a home health aide. Try as she might, though, she couldn't get a birth certificate. That meant she couldn't get a driver's license or register to vote.

See also: Voters' champion Brenda Williams.

"I fought with them and fought with them," she said of the local and state officials. "I prayed and prayed." In time, said Suggs, 62, who lives in Sumter, S.C., "I gave up on things" — like voting.

Having a driver's license or photo identification card is commonplace for most Americans, but about 11 percent of adult citizens — more than 21 million people — lack a valid, government-issued photo ID, according to a study by the Brennan Center for Justice at the New York University School of Law.

Increasingly, this puts their right to vote at risk. A year ago, only Georgia and Indiana required photo ID cards to vote. Since then, Kansas, Pennsylvania and Tennessee have joined the list, and similar laws in an additional four states have not yet been implemented.

The U.S. Justice Department has put laws in Mississippi, South Carolina and Texas on hold as potential violations of the 1965 Voting Rights Act, and Wisconsin's law was declared unconstitutional in March 2012 - a decision the state says it plans to appeal. In seven more states with photo ID laws, voters who are unable to show a photo ID are still allowed to vote if they can meet certain other criteria.

"What's new is the no-photo-no-vote" laws, said Jennie Bowser, a senior fellow specializing in elections at the Denver-based National Conference of State Legislatures. "The 2010 elections' big shift toward Republican control of state legislatures was certainly a piece of that."

Older voters most affected

The trend alarms voting advocates like Lawrence Norden, acting director of the Brennan Center's Democracy Program, who said photo ID laws hit older people, the poor, African Americans and students the hardest. "This is the first time in decades that we have seen a reversal in what has been a steady expansion of voting rights in the United States," Norden said. "There's no question that citizens over 65 will be particularly impacted. The older you get, the more likely you won't have an ID."

Nearly one in five citizens over 65 — about 8 million — lacks a current, government-issued photo ID, a 2006 Brennan Center study found. Most people prove their eligibility to vote with a driver's license, but people over 65 often give up their license and don't replace it with the state-issued ID that some states offer non-driving residents. People over 65 also are more likely to lack birth certificates because they were born before recording births was standard procedure.

Strict new photo ID laws could make voting this year more difficult for millions of voters, if the new laws stand, according to the Brennan Center.

In the states with strict photo ID voting laws, voters who show up without photo IDs generally are allowed to vote a provisional ballot that is counted only if the voter brings a photo ID to a government elections office within a few days, and may not be counted at all unless the election is close.

Next: Will strict photo ID laws cut down on voter fraud? >>