Billy Strathmann of Chevy Chase says he is the shortest person in his high school. At 14, he is 4 feet 10. Billy is accustomed to the jokes of his classmates.

"When I get pushed out of the line I just throw all my weight back into the line. . . . A lot of times my friends will say 'Billy, Billy' and pretend I'm not there," he says.

Says Harris Chadwick, 13, of Reston, "I'm the second shortest person in my school and lots of times my friends will pretend like they don't see me. Then they'll say 'Oh, there he is' and stomp their foot down like I'm an insect or something. I don't think it's very funny."

Billy, Harris and their parents, and about 40 other families, are members of the Greater Washington Chapter of the Human Growth Foundation, which meets each month at the National Naval Medical Center in Bethesda to discuss the pituitary gland malfunctions that have stunted their children's growth and other forms of dwarfism.

Unlike a heart, which has four chambers, the human pituitary gland has only two sections: an anterior and posterior. Within the tiny anterior lobe, usually smaller than a penny and neatly tucked beneath the base of the brain, six vital hormones are synthesized like clockwork from birth to death.

One of these hormones in particular dominates the conversations of the growth foundation members. It is called simply the human growth hormone and it determines how fast and how tall a child will grow, or whether the child will grow at all.

At each Washington chapter meeting, the children whose bodies have stopped making growth hormones meet in a separate room with two social workers while their parents talk nearby.

The children look normal, yet much younger than they really are. Harris Chadwick, 13, is 4 feet 3; Monica Mozon of the District, 8, is 3 feet 7; Billy Strathmann is 4 feet 10; and the group's most afflicted member, Hope Freeland of Gaithersburg, is 2 years old and weighs only 7 1/2 pounds.

Most of the children receive growth hormone injections and are growing, though at a very slow rate. Doctors tell them that in due time they should reach normal height.

Harris Chadwick, whose mother Sheila was a cofounder of the Washington group in October 1980, first showed signs of slow growth when he was 3. He has been taking growth hormone injections every other day for the past five years.

Human growth hormone, also called somatotropin, must be extracted from the pituitary gland after death. A synthetic hormone is being tested in 10 laboratories in the United States and is in the last experimental phase before being recommended to the Food and Drug Administration. Doctors predict it will be at least two years before a synthetic hormone becomes commercially available. Until then the natural hormone will continue to be expensive and hard to get.

"One pituitary (gland) yields about 10 international units of growth hormone. Most children require six units of growth hormone per week, and more is required for older children. So it takes about 25 pituitaries, or dead bodies, to supply one child with the hormone for a year," explains Dr. Val Abbassi, a pediatric endocrinologist at Georgetown University Hospital, and the chapter's other cofounder.

The National Pituitary Agency allocates growth hormones to selected endocrinologists in the United States each year. Although the hormone is free, children must be accepted as part of a research project conducted by an endocrinologist to get it.

"Most of the endocrinologists who treat hormone patients don't charge them. . . . If a patient's insurance does not cover office visits we try not to charge them," explains Abbassi.

Only two pharmaceutical companies in the world sell the growth hormones: The Kabi Group Inc., a Swedish company, and Serono Laboratories Inc., based in Italy. Both companies sell the hormone for about $15 per unit. At that price it would cost the average patient approximately $5,000 annually to maintain dosages of six units a week.

"There are about 2,000 children throughout the U.S. receiving some form of hormone treatment; . . . about 100 or so live in the D.C. area," Abbassi said.

The bond among parents whose children have stopped growing is strong.

Last month's chapter meeting, for example, drew 24 members from as far away as Vienna and Gaithersburg on Super Bowl Sunday and despite five inches of snow blanketing the metropolitan area.

In addition to medical problems, parents often discuss the pain of hearing their children talk about the frustrations of abnormal shortness and their all-too-often heartbreaking stories.

"One day my son came home crying because the teacher asked him to turn off a light and another kid rushed to do it and said my son couldn't reach the light. All my son kept saying was 'I know I could have reached that light, I know I could have,' " said one parent.

Hilda Evans of Herndon told a similar story. "My daughter came home fuming one day because a bunch of girls said, 'You're not nine years old, there's no way you can be nine years old.' "

In the next room, as social workers Ellen Rodin and Geri Elias urge the children to explore their feelings, the stories are harsher.

Monica Mozon finds the cruel jokes tough to take. As she looks over the top of her glasses, her soft voice cracks and she slowly tells a story she'd rather forget.

"Sometimes when I'm at school and I'm in line the kids will step on my foot and say 'Oh, I think I just stepped on Monica.' Then they'll pick up a rock and scare me with it."

Besides the pituitary's failure to produce the growth hormone, there are two other types of growth retardation.

Turner's syndrome, discovered in 1938 by Dr. Henry Turner, is the most common form of dwarfism, afflicting about 5,000 to 6,000 girls in the United States. Girls suffering from the disorder are born without ovaries, never go through puberty and, consequently, look like young girls all their lives.

The most physically evident form of growth retardation is achondroplasia, or bone dwarfism. One child in every 40,000 births is born with the disorder, which results in extremely short stature, an abnormally large head and an exaggerated forward curve to the lower spine. No cure or treatment for achondroplasia exists.

In some cases doctors cannot even find the cause of a problem. Hope Freeland, in her two years of life, has remained such a medical mystery. Her father, Ned Freeland, who works for the Internal Revenue Service, explains how he's come to accept his daughter's delicate size of 7 1/2 pounds.

"Part of the reason we accept her condition is because she was very sick when she was born and had to stay in George Washington University Hospital, where she was born, for four months. . . . She had a urinary tract infection and pneumonia, and had to have heart surgery when she was 16 days old. . . . Her inability to grow was the least of our worries."

Hope has been getting human growth hormone injections daily for the last year and has grown three inches in that time. However, doctors have no clues as to why the frail little girl will not grow on her own.

On Saturday, the National Board of Directors of the Human Growth Foundation, which has more than 600 families as members of 17 chapters, will meet at the Stouffer's National Center Hotel in Crystal City.

According to Chadwick and Abbassi, some members have suggested that the organization's headquarters, now in Minneapolis, Minn., be moved to Washington. Chadwick said she expects the move to take place although it has not been officially discussed.

Albert Evans, of Herndon, will become a member of the national board of directors in May, representing the Greater Washington Chapter of the foundation.