i have heard that gym workouts stops our height growth .. is it true?

Hello Jaya,
I have heard of this mostly with children…other aspects could be geneitcs, nutrition and types of exercises a youth performs.

http://www.livestrong.com/article/441421-a-list-of-exercises-that-stunt-…

http://en.wikipedia.org/wiki/Epiphyseal_plate

http://www.dukehealth.org/health_library/health_articles/your-growing-bo…

(See: The Role of Exercise and Physical Activity on the Epiphyseal Growth Plate on the link below)
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3194019/

The effects of exercise on the epiphyseal growth plate needs further research to comprehend the entirety of this dynamic anatomical and physiological entity. Research in the area of the epiphyseal growth plate in some children who are sedentary needs to be addressed.

source: Journal of Clinical Medicine Research

I Hope This Helps!
Michael