With school districts looking for applicants to fill a growing number of openings for teachers, some are asking if a teaching shortage is cheating students out of a solid education.

Teachers' unions and others believe a formal credential and an advanced degree are key requirements to being a good teacher. But others, like U.S. Education Secretary Rod Paige, say we shouldn't turn a blind eye to other candidates who are ready, willing and able.

"I don't subscribe to the idea that there is a shortage of teachers," Paige said during a tour of schools last month in San Diego. "I think there are some systems that block people out of the teaching profession who would be wonderful teachers."

Groups like the American Federation of Teachers generally oppose so-called alternative certification programs, and insist many simply aren't up to standard.

"Some can be like, ‘here’s your certificate, go in the classroom and close the door behind you,’" said AFT spokesman John See. The union has long held that there is indeed a teacher shortage, caused by "working conditions and teacher salaries," according to See.

But others believe the quality of alternative credentialing programs have vastly improved in recent years.

"All of the alternative route programs created in the last five to seven years are really very good programs in terms of preparation of teachers for the classroom," said Dr. Emily Feistritzer, president of the National Center for Education Information.

Given that, some educators said, it's only natural to look for qualified teachers from such programs.

"Looking at alternative methods to either credential or find highly qualified individuals that we can teach just absolutely makes sense," said Deborah Hirsh, chief recruiter for the Los Angeles Unified School District said.

One key advantage of alternative programs is that they "train people to teach in schools that they wind up being teachers in," Feistritzer said. "Most of the young white females getting degrees the traditional way don’t want to teach in inner cities or outlying rural areas, and that’s where demand for teachers is greatest."

One alternative program, Troops to Teachers, assists former military personnel who would like to enter the public education system.

"Individuals that have been in the military generally have done a lot of instructing throughout their careers, not teaching in the purest sense, but they've developed curriculum, taught classes … they bring a lot of leadership," Hirsh said.

But wanting to teach and being able to do it aren't necessarily the same thing, argued Adrienne Harrell, of the Center for the Future of Teaching and Learning. Harrell cited a report that found only 5,000, or about 12 percent, of the 40,000 teachers without credentials have advanced degrees.

About 40 percent of credentialed teachers hold either masters' or doctoral degrees, the study found.

But non-traditional programs are already in place in many places around the country.

In 2002, 45 states and the District of Columbia reported having some type of alternative teacher certification program, compared with only eight states in 1983, a study found.

See said he sees "market forces at work" in the growth of alternative programs, a sign of desperation among school districts.

"Districts that feel the pressure to fill slots may wave some requirements or set up some program that really doesn’t prepare the candidate that well," he said. "It’s unfortunate."

But good teachers can — and should — be found in some rather unlikely places, stressed Hirsh.

"Lawyers, engineers, nurses, entrepreneurs — we even have the owner of a fast-food chain who decided he had a calling to teach, and now he's teaching in Los Angeles."

Fox News' Anita Vogel contributed to this report.