It was a community of around 200 Chinese people. Average height of the kids was 5 feet 8. This was in the 70s. At least 5 or 6 kids out of 50 boys were over 6 feet tall. I am 6 feet with shoes. Of course nutrition was good. I ate a lot of meat, fish and dranks gallons of milk. Playing basketball helps too.  My father was five feet 5 and my mother around 5 feet tall. Diet and lifestyle is very important for growth. It's not unusual to find Cantonese boys over 6 feet tall in Guangzhou nowadays. In Shanghai, all the young kids are closer to 5'9 average.