At five-feet tall, 13-year-old Daniel Clark of Harlem in New York City is considered one of the easier boys to pick on simply because he is shorter than the rest of his classmates.
"He had been attacked, mugged, five times outside the school," said Daniel's father, Daniel Clark Sr. "Every time he leaves the house you have to, 'oh my God, hope nothing happens to him.'"
Daniel has always been around the bottom tenth percentile for height. At his previous school, Daniel said was cut from sports teams, picked on, and had to work harder to prove his talents because of his height.
"I may be short in appearance, but not in personality," Daniel said.
Unlike his son, Daniel Clark Sr. was already 6 feet tall when he was his son's age. And although his mother is five feet tall, doctors said they are uncertain how tall Daniel will grow. His father says it's hard to watch his son feel so set back because of his height.
"He's a nice guy, who in terms of stature happens to be small in size," said Clark. "We've both been thinking perhaps he might get a growth spurt."
Concern about the slow growth of a child is common among parents and anxiety is often greater when the child is a boy, according to a study published in the British Medical Journal.
For boys, growth spurts occur around age 13, but may begin as early as age 10 or as late as age 16. And on average, girls will have their greatest growth two years earlier than boys, said ABC News Senior Health and Medical Editor, Dr. Richard Besser.
However, according to Dr. Joseph Zanga, chief of pediatrics at Columbus Regional Health Care System in Columbus, Ga., each child has a different growth potential.
"Even a child at the 50th percentile may be normal, "he said, "but if they're whole growth life they were at 90th percentile of growth and then drop to the 50th percentile, normal is not necessarily normal then."
Children are generally considered of short stature when they are shorter than 98.8 percent of other children of the same gender and age, according to the Food and Drug Administration. While factors like eating right and plenty of physical activity help ensure a child grows normally, genetics also plays a major part in determining how tall a child will grow, said Zanga.
"If everybody in my family never gets taller than 5 feet, then I will be content that my son has reached his potential," said Zanga. "If all of my family is 6 foot tall and my child doesn't look like he's going to make it at all, I might be concerned."
According to Besser, parents should talk to a pediatrician if their child is growing less than two inches a year, if a child is not gaining or losing any weight, or if a child is frequently coughing or experiences infections.
Severe obstacles to growth for some children include malnutrition, thyroid deficiency, or heart and lung diseases. Pediatricians use history and physical evaluations that may include taking a closer look at the aging of the bones through x-rays to understand what is hindering some children to grow.