When Fairfax County school officials made plans to merge Groveton and Fort Hunt high schools this fall, one thing they did not make room for was Groveton's controversial program that allowed some teen-age mothers to bring their babies to school.

For the past three years, teen-age mothers living in eastern Fairfax could attend Groveton, where they took regular classes, participated in child care lessons and left their children in a school-based day care program until the last class bell rang. Between 11 and 15 teen-age mothers were enrolled last year.

This year, however, the Groveton program -- the only one of its kind in the county -- has suddenly been squeezed out, a victim of the school's merger, which nearly doubled the school's enrollment to 2,385 students and left all classrooms in the newly named West Potomac High School occupied.

"We don't have any room," said Paul Douglas, principal of the new school. "We're using every square foot."

The teen-age mothers who had planned to attend Groveton are being offered the chance to go to nearby Edison High School, where they can take child care courses. In addition, the county has offered to find day care for the children, said Verdia L. Haywood, the deputy county executive for human services.

However, the shift of the program out of Groveton has given county officials the opportunity to study the larger question of how Fairfax will educate teen-age mothers in the future.

Officials said they are considering whether there should be more teen-age mother programs, whether they should be scattered around the county or centralized, and whether the Groveton program was the success its proponents claim it was.

"We're still in the process of determining exactly where we would go; would it be the same kind of program -- looking at all the options," said Herman Howard, a deputy school superintendent. A recommendation is expected to go to the county Board of Supervisors this fall.

There were 550 births among Fairfax women age 19 and under in 1982, the most recent year for which county statistics are available, and Groveton is able to accommodate only a small percentage of that number.

Without some incentive to stay in school, many young mothers drop out, and some eventually wind up on welfare rolls, program proponents say. Also, many teen-age mothers need the information about child nutrition, development and other topics that the program provides.

Program opponents have claimed in the past that such help might encourage girls to have babies by making single motherhood easier and more socially acceptable. And they have complained that taxpayers should not be forced to pay for others' mistakes.

"I thought it was a good program," said Joan Hartman, the home economics teacher who launched the Groveton program three years ago with a $10,000 March of Dimes grant. "I think it's needed."

"It's a controversial area," said Douglas, Groveton's former principal. "I think not everyone agrees it's something a school should be doing. But I do think there's just a tremendous need."

Last year, the Groveton program cost Fairfax $13,411 and an additional $12,645 in federal funds. Haywood could not predict this fall's costs but expected them to be somewhat less.

School Board Chairman Mary E. Collier said day care for babies of teen-age mothers does not appear to be a priority issue. Of the 116 high school students who Fairfax officials said had babies in 1983, only 16 dropped out of school, she said.

"The need does not seem to be as great as perhaps we might have feared initially," she said, adding that only about 15 young mothers signed up for the Groveton program, although it was available to women from around the county.

"We need to deal with such questions as: 'Is it in the girl's best interest to carry children to school?' and, 'Is it in the best interest of the other students?' " she said. "What we want is to help all high school-age children, and we need to know how best to do that."