With more than 60 percent of Dulaney High's seniors taking tough college-level Advanced Placement classes, their principal has fewer worries about achievement than most administrators.

Instead, she worries about students taking too many difficult classes.

So as Baltimore County prepares to change high school schedules in the fall to allow students to sign up for one more class a semester, Lynda Whitlock recently decided to enact a policy that ensures students fully consider the consequences before they take more AP classes.

"As an administrator I definitely have a concern," Whitlock said. "We are looking out for their total well-being. We don't want anyone taking more than they can handle."

Counselors review course registrations for the coming year with every student, but those who take more than five Advanced Placement classes will also have a conference with Whitlock so that she can discuss the courseload and stress on students.

Whitlock said, however, that the final decision will be up to parents. There are some remarkable students who are able to handle the workload, she said, citing a Dulaney student who achieved a perfect score on an AP economics exam last year, one of the very few to do so in the country.

Some parents and educators across the country have begun questioning an education system that encourages students to take a large number of AP classes to gain acceptance to colleges.

"The extreme pressure on kids to enroll in AP courses — for the sake of saying 'I took [blank] AP courses and [blank] AP exams' — contributes to the message already being sent to them when we place so much emphasis on grades and class rank: that it's not learning that matters most; it's what can be put on a transcript and easily enumerated," said Cindy Moore, the parent of a Baltimore County high school student.

Some high-performing students are now taking 10 to 12 Advanced Placement classes during high school, a courseload that some education experts criticize as too heavy. The system rewards those students' schools as well, because some national rankings are based solely on the number of AP classes a school offers.

Like Whitlock, Baltimore County administrators are reluctant to limit the number of AP classes students can take. Maria Lowry, the county's assistant superintendent for high schools, said those decisions are made individually by students in collaboration with their families and school counselors.

"It is something principals and guidance counselors have always paid attention to," said Lowry. "Usually there is a review of each student's registration. So I don't think the schedule change will have much of a difference at all."

Other counties also have made no attempt to slow an explosive growth of the use of AP in the past several decades.

"We currently do not have a limit on the number of AP courses a student can take, but our guidance counselors work with students, teachers, and parents to help make the best choices," Howard's spokesman, Rebecca Amani-Dove, said in an email.

In Baltimore County, the schedule changes could potentially allow students to take another four AP classes during high school.

Baltimore County schools Superintendent Dallas Dance said he wanted to make the schedule change to give struggling students more time to gather enough credits to graduate from high school.

A number of Baltimore County's high schools are on a seven-period day schedule, but Dance decided last year that all schools will have to switch in the fall to an eight-period day or a four-period day with alternating classes. That change will give students less time for each class, but allow them greater choice of classes.

Amy Nozemack, the mother of twins at Hereford High School, is working with other parents to try to persuade the county school system to drop the move to force every student to take a schedule of eight classes each semester.

She said Hereford students currently take four classes. "It enables students to focus on four subjects at a time," she said.

If the county goes ahead with the schedule change, she said, she will only allow her daughters to take one AP class next year, rather than the two they were planning to take.

"I think having eight classes to focus on at one time is a big difference, and it increases the stress level for the kids," Nozemack said.

Jeremy Goldman, head of school counseling at Pikesville High School, said a handful of students at his school are taking AP classes every period in the day, but he doesn't believe most students will be adding another AP class to their schedules.

"I don't think our kids are going to be looking for more AP," he said, adding that there's instead an increased interest from high school students in taking community college classes for free and getting college credit.

Lowry said it is important that all students have access to AP classes and that the school system offers support when students aren't doing well.

"In some cases, students didn't pass the [AP] exams but they felt they were successful," she said. "They learned how they had to prepare, how they had to study."

liz.bowie@baltsun.com