Some Members of Congress get their jobs the old-fashioned way: By apprenticing for them.

Since World War II, the number of seats in Congress occupied by former Congressional staffers has dramatically increased, with many in the positions once held by their former bosses.

In the current session of Congress alone, 75 one-time staffers are now Members, according to CQ's Politics in America. Of this group, a survey by Congress.org found that over two dozen inherited the seats of retired Members they once worked for .

And at least six staffers are currently vying for seats in elections coming up this year.

A number of factors leave staffers uniquely prepared and well positioned for a Congressional run at some point in their political careers, said Paul Herrnson, director of the Center for American Politics and Citizenship at the University of Maryland, College Park.

"Historically, Congressional aides have had tremendous advantages in running for office, and today they still enjoy those advantages," said Herrnson. "They know the issues, they have elite connections, they have fundraising advantages … and they are often networked enough in the district to have local activists and interest groups host them at parties and those kinds of events."

Staffers also have the upper hand when a Member retires after years of loyal service and high approval ratings, since they can offer voters the promise of continuity and a smooth transition.

They sometimes struggle, however, when it comes to facing off against local officials with greater name recognition at home, experts say. In addition, they may also have difficulty shedding the label of the "Washington insider," especially in times when the capital has fallen out of favor.

"Incumbents don't even run as insiders now," said Christopher Deering, a politics professor at George Washington University. "There's a general distaste with Washington politics and the incivility of it, more so than usual."

Before World War II, it was more unusual for a staffer to work their way up because there were only a few personal aides on Capitol Hill. In 1946, Congress passed the Legislative Reorganization Act, which streamlined Congressional committees and allowed Members to hire larger staffs.

With more staffers getting to know the ins and outs of Congressional life, it became more likely that some of them would want to run for office themselves.

By the 1970s, it was already becoming easy to identify Members who had begun their professional careers as Congressional aides. In a 1994 study, Paul Herrnson discovered that between 1978 and 1988, 2.6 percent of non-incumbent candidates came from strictly a staff background.

While it may seem like a small sum, his numbers showed that candidates who ran for office with that background were more likely to beat their opponents in primary and general elections — even previously elected officials.

In 2004, when CQ Politics in America first began taking headcounts of staffers-turned-Members, 69 were identified as having once worked for a Representative, Senator, or committee; of that number, 26 were elected to the seats of the Members for whom they used to work.

Of the 75 former Congressional staffers who are office holders today, 30 of them were first elected to succeed their former bosses.

These numbers might go up in the months ahead, as a handful of candidates this election cycle are hoping to join the legacy of staffers-turned-Members.

There are currently three candidates looking to move into the vacant, or soon-to-be-vacant, seats previously held by their old bosses:

• Chad Causey recently resigned as chief of staff to retiring Rep. Marion Berry (D-Ark.) to launch a campaign for the seat.

• Stovall Witte is another former chief of staff who wants to succeed his old boss, retiring Republican Rep. Henry E. Brown Jr. of South Carolina.

• Mark Critz, district director for the late-Rep. John P. Murtha (D-Pa.) has been named the Democratic nominee in the upcoming special election to succeed him.

Then there's Princella Smith, who just gave up her job as communications director for Rep. Anh "Joseph" Cao (R-La.) to vie for Berry's seat. And Jack Bailey, former chief of staff to Rep. Todd Akin, R-Mo., is hoping to be the Republican challenger to Democratic Rep. Lincoln Davis of Tennessee.

Ed Potosnak is another hopeful challenger on the Democratic ticket to incumbent Rep. Leonard Lance (R-N.J.). He recently left the Capitol Hill education policy staff of Rep. Michael M. Honda (D-Calif.), where he has worked for two and a half years, to launch his campaign in the New Jersey district where he has his roots.

Potosnak told Congress.org that his background will likely resonate with voters: he spent years as a high school chemistry teacher with a small home improvement business to supplement his income, and he is still paying off his student loans.

But his experience working on the Hill, he added, should also work to his advantage.

"Sometimes people refer to me as a 'staffer,' but I see myself a lot more as a teacher and a small businessman than a staffer," he said. "But I do think the experience working on the Hill provides an excellent skill set you need as a legislator, so I don't think it's going to be a negative for me …

"It's important that voters understand I have real world experience and legislative skills, that I know how to get things down in Washington, that I know how it does its work."

Emma Dumain writes for Congressional Quarterly.

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Correction: The number of staffers who were elected to replace their former bosses has been updated.