Weight lifting/physical fitness WILL NOT, CAN NOT, DOES NOT stunt your growth!!!!
In fact is has been scientifically proven that proper weight training can stimulate the pituitary gland to produce more Growth Hormone (GH), which may have a positive affect on someones overall height. Also, persons who are into weightlifting and physical fitness tend to take better care of themselves, which can allow their body to maximize its overall height potential.
Only 3 things can change or "stunt" normal human growth:
Excessive, Chronic Drug Use
Massive injury to an individuals spinal cord may affect their overall height, but the body would still "grow" to its predetermined height and size. So even a weightlifting injury would not "stunt" growth.
Was just making this clear!