Democratic first lady hopefuls include a doctor, a lawyer, a philanthropist, a military wife and even a former backup singer for James Brown.

Though they've stayed in the background to date, the wives of the Democratic presidential candidates will likely become more prominent, familiar figures as the race heats up, say experts.

"The public likes to see a candidate who has a good family life and a nice wife," said Paul F. Boller Jr., author of "Presidential Wives" (search) and retired history professor at Texas Christian University.

In fact, some experts say wives have become crucial to a candidate's election to office.

"There was a time when we probably wouldn't have even seen the spouse," said Mary Regula, founder and president of the National First Ladies' Library in Ohio. "Now they're a real asset to a campaign."

First lady duties include running the White House social calendar, acting as hostess during dignitary dinners and visits, undertaking at least one charitable project and giving press interviews and speeches.

Regula, the wife of Ohio Republican Rep. Ralph Regula, said the qualities voters want in a first lady are similar to those they like in a president.

"We look for that down-home friendliness and humor," she said. "There has to be a certain warmth that ordinary people can relate to."

Some analysts say they believe the candidates' wives have what it takes to fill the first lady's shoes.

"All the wives of the Democratic candidates have had experiences that would enable them to play the role of first lady," said Fox News political analyst Daedre Levine (search).

Judith Steinberg Dean (search), wife of former Vermont Gov. Howard Dean, is a doctor with her own medical practice. Steinberg Dean, 50, a Princeton graduate, uses her maiden name professionally and plans to continue practicing medicine in Washington if her husband wins. The couple has two teenaged children.

"She'd be the least likely first lady," Levine said. "She'd be a breath of fresh air in the White House."

North Carolina Sen. John Edwards wife, Elizabeth Anania Edwards (search), is a lawyer but hasn't practiced since 1996, when she and her husband quit their legal practices after their son died in a car accident. Mrs. Edwards, 54, spends a lot of time with the couple's other three children and does community service work.

"She's a lot like Hillary [Clinton] in the fact that she's smart, opinionated and a lawyer, but she comes across as softer than Hillary," said Fox News political analyst Eleanor Clift (search). "She could get away with some of the things Hillary couldn't."

Teresa Heinz Kerry (search), wife of Massachusetts Sen. John Kerry, is the widow of ketchup fortune heir Sen. John Heinz and thus a seasoned political spouse. The 65-year-old Heinz Kerry grew up in Africa and now heads the billion-dollar Heinz family philanthropies. She has three children from her first marriage.

"She could adapt to the job easily," predicted Clift, contributing editor at Newsweek. "She is used to being a benefactor and that's what a first lady does."

Gertrude Kingston Clark (search), wife of retired Gen. Wesley Clark, is a longtime military spouse who has done volunteer work for the National Military Family Association and Sen. Kay Bailey Hutchison, R-Texas. Kingston Clark, 59, had experience meeting with dignitaries when her husband was NATO Supreme Allied Commander for Europe.

"Gert Clark is the closest to the traditional president's wife," Clift said. "She always had to put his career first."

Kathy Jordan Sharpton (search), wife of the Rev. Al Sharpton, is a former backup singer for James Brown. Her career has also included stints as a U.S. Army sergeant, an activist and a school choir director. The couple has two teen-aged daughters.

Ohio Rep. Dennis Kucinich is the only divorced candidate in the running. James Buchanan was the sole U.S. president who didn't marry; five others remarried after their first wives died.

The current president's wife, Laura Bush (search), tends to stay in the background and keep a low profile and is known to hate the "first lady" title. A former librarian, the 57-year-old Bush has undertaken literacy as her cause.

But whether they embrace or shun the spotlight, many first ladies have had a tremendous impact on U.S. policy.

"These women have contributed so much to our nation's history," said Regula.

Nancy Reagan was one of the most powerful first ladies in history, according to Boller. Rosalynn Carter, Eleanor Roosevelt, Hillary Clinton and Bess Truman also had distinctive influence. All were known to have been among their husband's most trusted advisors.

"Some of them have been very, very influential and helped their husbands very much in the White House," Boller said.

And if one of the Democratic candidate's wives ends up as the next first lady, she'll inherit an automatic allure.

"There is a fascination with first ladies," Regula said. "The first family is a little like our royalty."