Dr. Lillian McLean Beard of Potomac, recently named one of the nation's top 10 young women of the year, is in the early phases of a long-distance run.

Most people would say she can afford to sit back and relax -- the 35-year-old physician has come a long way from the Brooklym slum where she grew up. She has a thriving pediatrics practice in Northwest Washington, a solid professional reputation and seats on the boards of dozens of organizations.

Beard says, however, that "I don't feel I've made it.

"I don't want to sound like I'm being grandiose," she continued, "but I want to make a major contribution in the health services."

She has already contributed enough to earn the award from the Outstanding Young Women of American organization. The awards were presented during a ceremony at the Washington Capital Hilton this week.

Beard, a handsome, stately woman, has been winning in the numbers game all her life.

In high school she was one of five black students in a class of 1,055. In Howard University School of Medicine, she was one of 15 women in a class of 100. Now she is one of two blacks among the top 10 women in the nation.

Her seven-page, double-spaced resume is an exhaustive listing of citations, and professional and civic accomplishments. The personal telephone book she keeps in her purse has extra pages stapled into it with names spilling over into the Z section.

Beard pursues life almost as though she'd been told she had only a year to live and wanted to cram everything possible into that time. Besides her busy practice and many civic commitments, she takes French, piano and dance lessons and plays tennis twice a week. Asked what she would choose if she had only one wish, Beard didn't hesitate. "I would choose to have 10 more," she said.

Beard and her husband, an attorney, left the city to move to a five-bedroom house in the Montgomery County community of Potomac.

"It doesn't matter where we live. It doesn't affect our social commitment," she said. "All my endeavors are in the city. All my time and energy is spent in the inner city."

Beard's pediatric practice is in a mostly black area of Northwest Washington.

"I feel the quality of life of a large segment of the population leaves something to be desired," she said, measuring her words in a slow, lilting cadence. "I feel committed to making a change."

Sometimes change can start with a 4-month-old child.

"What's all this stuff about diarrhea and vomiting you've been having?" Beard asks Kiara Hill, not, of course, expecting an answer. "Hi, sweetheart. What's the matter?" she asked with maternal concern when the baby started crying.

"I think you're a faker," she concluded when the baby slipped a thumb into her small mouth and sucked contentedly.

Dressed in a yellow smock painted with bright tulips, Beard asked Kiara's mother about the child's development, and feeding and sleeping habits. Handling the baby, Beard seemed more like family friend than a doctor.

"The children really like her," said Delores Huddleston, who has been coming to Beard since Carol, now 5 1/2, was born. Huddleston lives in Southeast, but said the long trip to see Beard is worth the time it takes.

"She takes the time to talk to you about your child," Huddleston said. "You end up waiting a little longer, but when it's your turn you're glad. All our questions are answered." l

The waiting room is furnished more like a nursery school than a doctor's office, with toys, a small slide for the toddlers, and books such as "Bible Stories" and "Aesop's Fables."

"We look at the child as part of the family and part of the community and not just at the physical symptoms," Beard said.

The doctor believes that to bring about change in health care, there must be change in the students admitted to medical schools. She serves on the admissions committee of the George Washington Unversity School of Medicine and advocates the entry of more minority students.

"Admission to professional schools is readily available to a certain segment of well-prepared young people. It isn't for people who come from families who did not gear them up from the eighth grade."

Beard was preparing for medical school even before she got to the eighth grade.

"I can't remember when I didn't want to be a doctor," she said.

When she told her elementary school teachers about her ambition, some corrected her, saying she must mean that she wanted to be a nurse.

But Beard's mother, who raised her two daughters alone while juggling two jobs and attending college, told her girls they could do anything if they put their minds to it.

"My mother never tolerated my saying I couldn't do something. She would always tell me to at least try."

When she was 11 years old, Beard was tall for her age and would slouch in futile attempts to make herself shorter.

"My mother told me to stand tall and be proud of what I am," she said.

The McLean family was considered "different" in the Fort Green project in Brooklyn, said Beard.

Mrs. McLean went to work every day, and the McLean children took piano and violin lessons in a neighborhood where most children got their lessons in the gritty streets.

"We took advantage of everything that was free. We went to museums and young people's concerts," she said.

Beard was graduated from elementary school at the top of her class, and expected to go to one of the neighborhood high schools.

Her mother had a diffrent idea. Mrs. McLean checked test scores for all Brooklyn high schools and determined that her daughter would go to the best: Midwood High School in Flatbush, two buses and a subway ride away.

The elementary school principal thought Beard's mother was presumptuous. He had tried to get a white child admitted to Midwood several years before and had failed.

"Who was my mother to think she'd get me in there?" said Beard.

Mrs. McLean appealed to the New York City Board of Education, and four years later her daughter graduated from Midwood.

"I used to tell her that as soon as she reaches one step on the ladder to continue to reach for the next one," said Mrs. McLean, who lives in Westchester County in New York state and still works two jobs although she longer needs to. "She seemed to have taken the lesson in," she said of her daughter.

At 35, Beard feels she is up against a biological clock and must soon decide whether she wants to have children. She has put off having children, she said, because of her lifestyle and her love for travel.

"I get to work on my maternal instincts all day," she said, and smiled.

People who know Beard were not surprised to hear about her most recent award.

"I would expect nothing else from her," said Altovis Gore Davis, wife of singer Sammy Davis Jr. and Beard's childhood friend.

"There are a lot of black women with an untapped potential," said Beard. "There are many who have made it and many more who will make it. I've been lucky to have been recognized."

Another local woman who placed among the top 10 is Sarah Weddington, special assistant to President Carter. The 34-year-old Texas lawyer filled the White House post vacated last year by Midge Costanza.