From the New York Times. ORLANDO, Fla. — Every year, more than 600,000 academically promising high school students — most of them poor, Latino or black — fail to enroll in Advanced Placement courses, often viewed as head starts for the college-bound.

Some of them do not know about these courses, which offer an accelerated curriculum and can lead to college credit. Others assume they will be too difficult. But many are held back by entrenched perceptions among administrators and teachers, whose referrals are often required for enrollment, about who belongs in what has long served as an elite preserve within public schools.

“Many teachers don’t truly believe that these programs are for all kids or that students of color or low-income kids can succeed in these classes,” said Christina Theokas, director of research at the Education Trust, a nonprofit group. Ms. Theokas said that if those underrepresented students had taken A.P. courses at the same rate as their white and more affluent peers in 2010, there would have been about 614,500 more students in those classes.

In an effort to overcome those obstacles, an increasing number of school districts, including Boston, Cincinnati and Washington, have recently begun initiatives to expand Advanced Placement course offerings and enroll more black and Hispanic students, children from low-income families and those who aspire to be the first in their generation to go to college. In the spring, lawmakers in Washington State passed legislation encouraging all districts to enroll in advanced courses any student who meets a minimum threshold on state standardized tests or the Preliminary SAT exam.

While some critics say A.P. classes are little more than another round of test prep, supporters say they can foster a culture of learning. Humberto Fuentes, a senior here at Freedom High School taking his first A.P. classes, in English literature and economics, said they were the first time he had been around peers who enjoyed school.

“In regular classes, people are trying to distract you with music videos or saying, ‘Hey, look at this cat playing a piano’ on their phones,” said Humberto, 17, who emigrated with his parents from Ecuador when he was an infant and hopes to be the first in his family to attend college. “Whereas in an A.P. class, they will show you something from the text and say, ‘Hey, this is fun.’ ”