Marcia Malloy of Arlington recently read "Alligator River," an allegorical tale that 11th-grade American history students at Yorktown High School discussed last spring. Malloy, the mother of three young girls, said she became furious.

Here was a story, she said, with disturbing moral implications: a young woman in the story must decide whether to sleep with the captain of a boat in exchange for a ride across the river to see her lover.

"You send your child to school to get an education, not to discuss morals in such a haphazard manner," said Malloy. She and a group of other Arlington parents have demanded that before their children are subjected to any similar discussions the parents give written approval for their children to remain in the classroom.

While parental concern about classroom topics is not new, parent groups, such as the one to which Malloy belongs, are seizing on a new set of federal rules in an intensified effort to control what their children study. The rules are supposed to protect students from psychological testing that might invade their privacy, but teachers and educators across the country say parents are citing the regulations in an effort to control the content of classroom discussions.

"It is spreading like wildfire," says Dena Stoner, legislative liaison for the National School Boards Association in Alexandria.

The regulations, called the "Hatch Amendment regs" because they enforce a 1978 education amendment sponsored by Sen. Orrin G. Hatch (R-Utah), took effect only three months ago. Yet they have prompted a flurry of parental requests to examine teaching materials and to demand written consent before children study drug abuse, sex and other controversial topics.

The two-month-old, 30-member group called Parents for Academics to which Malloy belongs has raised objections, based on the regulations, to "Alligator River" and other stories. The group has asked the Arlington School Board to send parents consent forms before such topics come up in class.

Arlington teachers, including John Phillips, whose students discussed the controversial story, say that a classroom instructor cannot teach if every topic he or she raises is subject to being censored. Moreover, says Phillips, "Alligator River" provided an excellent way to get the students to discuss how people have to negotiate when they must make painful and difficult choices.

"There's no question that there is much more of a general trend of parent protest not against specific books but against the whole direction of a curriculum," said Dorothy Massie, a National Education Association staff member.

The National School Boards Association wrote last month to members of Congress about the "chilling effect that could be placed on the teacher/student relationship" if parents were permitted to veto "sensitive" subjects of discussion in class.

Malcolm Lawrence, founder of the conservative Maryland Coalition of Concerned Parents, says, however, that schools that teach about male and female roles, decision-making, moral situations and other controversial, "nonacademic" issues are "usurping the role of parents."

This latest and most intense round in the fight over what students should and should not discuss in school was sparked when the five pages of rules were published in the Sept. 6, 1984, Federal Register.

Officially called "Student Rights in Research, Experimental Programs and Testing," they require parental consent before students take part in federally funded "psychiatric or psychological experimentation, testing or treatment."

But a "psychiatric or psychological examination or test" is defined to include "a group activity, that is not directly related to academic instruction and that is designed to elicit information about attitudes, habits, traits, opinions, beliefs or feelings" -- a definition that some parent groups have interpreted broadly to include certain classroom studies.

If such activities explore seven "sensitive areas," the rules say, parents must sign consent slips for their children to participate. The seven topics are: political affiliation; mental and psychological problems; sex behavior and attitudes; illegal, antisocial, self-incriminating and demeaning behavior; critical appraisals of family members; legal relationships such as those of lawyers, physicians and ministers, and income.

The rules also outline a way for the Department of Education to handle parental complaints that cannot be resolved at the state and local level.

At the heart of the wrangling is a basic philosophical rift about discussions of subjects that touch on values and their interpretation.

Dorothy Stambaugh, an attorney and member of the Arlington School Board, said, "I certainly believe an education has to include more than rote memorization and learning of skills . . . . We have to teach [students] how to interpret the knowledge they get."

Lawrence disagrees. "A fourth grader," he says, "is not going to learn anything by having a teacher ask him how he feels about something."

Opponents of the rules, including the National Education Association, the National School Boards Association, and the National Parent Teachers Association, say the rules permit federal probing of curricula that should be the exclusive domain of local school boards.

Moreover, they worry that conservative groups may try to apply the rules broadly to strip curricula of any topics they find offensive.

Since the regulations took effect, according to Department of Education spokesmen, only three complaints have reached the federal level. But the rules have become a "sort of rallying point" for groups such as the Maryland Coalition of Concerned Parents, Lawrence said.

One result is a form letter that the coalition, which claims members from 140 parent groups around the country, circulated last month. It is similar to a letter published in the January newsletter of Eagle Forum, the conservative umbrella organization founded by Phyllis Schlafly.

The letter, which parents send to school board presidents, asks that parents be sent written consent forms before students participate in any of 34 activities.

If all the topics listed were excised from the classroom, "it wouldn't leave much room for teaching and learning," said Massie of the National Education Association. "It would just put a blanket of silence on public school classrooms."

Supporters of the federal regulations claim they are not trying to censor sensitive topics but feel parents should know and agree in advance when their children will be studying such topics.

"I can't imagine any sort of worthwhile curriculum that would be threatened" by the rules, contended Tom Moore, a Department of Education spokesman.

Opponents, however, say the burden of sending parental consent forms would make teachers hesitant to treat sensitive issues at all.

On the federal level, a coalition of groups dissatisfied with the regulations recently has moved its fight from the Department of Education to the halls of Congress, according to lobbyists for groups such as the National Education Association and the National School Boards Association.

In Arlington Parents for Academics also objected to a seventh-grade class reading part of the script from "Testament," a television movie about a family facing nuclear holocaust. At the end of the excerpt read by the Williamsburg Intermediate School class for gifted and talented students, the mother and son contemplate suicide, then decide it is better to live.

When such disagreements arise, School Board members themselves often cannot agree on the correct course of action. "I wouldn't want my child involved when they sit around and discuss sexual behavior or suicide . . . . I just don't think that's appropriate," Arlington School Board member Margaret A. Bocek said at a recent board meeting.

"I still have not calmed down from hearing that ["Alligator River" was used in school]; it really upset me," School Board member Simone J. Pace said at the last board meeting.

Other board members say such issues are unavoidable in discussions of literature, history or current events.

"The entire subject of Romeo and Juliet is a double teen-age suicide based on a love tryst. Are we going to have prior parental approval for teaching that?" Stambaugh asked.

So far, the struggle of views has yielded few answers. Arnold Fege, director of governmental relations for the National PTA, says some parents' concerns about classroom materials are legitimate and he urges them to get involved in developing and planning curricula rather than reacting after the lessons are in place.

Marjorie McCreery, executive director of the Arlington Education Association, says it is crucial, particularly in highly diverse communities such as Arlington, for teachers to encourage the critical thinking and questioning that seem threatened by the recent parent complaints.

"We're trying to get these kids to live together," she said. "You can't avoid values."