WASHINGTON - Most healthy children between the ages of four and 10 grow about five centimeters (two inches) a year. So, one family knew something was wrong when their son fit into the same clothes, season after season. Doctors were able to get him growing once again after testing for a growth hormone.

Eleven year-old Spencer Baehman is passionate about baseball. 

"My goal is to play college baseball,” Spencer said.

There was only one problem. Spencer was the shortest player on his team. It didn't stop him from playing, but the height difference was noticeable. And it made Spencer feel different.

"I want to be as tall as these kids,” Spencer said.

At first, Spencer's parents thought their son was just small, but gradually, they suspected something was wrong. His mom, Stephanie Baehman, became worried. 

"It really set in one year coming out of winter into spring when he got out his cleats for spring baseball and he put them on, and they fit. And they never should have fit. Those were from the spring prior,” Baehman said.

Spencer's parents set up an appointment with Dr. Bert Bachrach, the chief of pediatric endocrinology at University of Missouri Health Care. Nurses measured Spencer's height. 

After careful testing, Dr. Bachrach determined a growth hormone deficiency was causing Spencer's growth failure. Hormones are basically chemicals that send messages from one cell to another. 

"Growth hormone just doesn't affect your growth, it affects your muscle mass and fat distribution, so that affects your cholesterol, that affects you overall, it also affects your overall sense of wellbeing,” Bachrach said.

Growth hormone insufficiency is a disorder involving the pituitary gland which is a small, pea-sized gland located at the base of the brain. It's this gland that produces human growth hormone, among others. 

Every day, Spencer's mother gives him a daily hormone injection. Since he started getting these injections two years ago, Spencer has grown about 15 centimeters (six inches). But just in case he doesn't grow tall, he has a reminder written in each of his baseball caps.

"It says HDMH, which means height doesn't measure heart,” Spencer read. 

And heart is something Spencer has plenty of.