No studies have shown a direct cause-and-effect relationship between caffeine intake and stunted growth. However, the claim might not be totally unfounded. A supporting argument might go like this: Human growth hormone (HGH), which promotes proper development, is secreted mostly during sleep. Caffeine is a stimulant, which excites the nervous system and can interfere with sleep. Thus, consuming caffeine indirectly hinders the production of HGH and limits growth.
To repeat: This argument, while logical, lacks scientific backing. And when you consider the other factors that affect growth, including heredity and nutrition, you can see how simplistic the explanation sounds.
On the other hand, here's some food (or drink) for thought: Caffeinated beverages have increased in popularity. According to reports from the beverage industry, coffee sales rose 9 percent in 2010-2011, topping $4 billion worldwide, and sales of caffeine-laced energy drinks grew 136 percent between 2005 and 2009, mostly due to increased consumption by regular drinkers.
Yet people are, if anything, growing taller. Reports from the CDC indicate that the height of the average American guy rose about 1.5 inches between 1960 and 2002, and the typical female added 1 inch to her stature. And the average Australian has shown a similarly slow but steady growth. Again, many factors affected this trend. But if it should reverse and the average height drops following this boom in caffeine consumption, then this old wives' tale might warrant a closer look.