If my two and a half years old grandson is grown up not as tall as his father, uncles or grandfathers and granduncles, the water may be to blame. 

Referring to my less than expected stature, my eldest uncle from Qingdao, Shandong, once told me that my family members of his generation were all grown up taller (above or close to 1.8 m) thanks perhaps to drinking water from the Yellow River, which maybe had some nutritious elements in it. In my mind, over a dozen relations of my generation in the family, only my two cousins from Qingdao were taller than/as tall as their father, my eldest uncle. Others are shorter than their fathers, me included, an evidence of the merit of the Yellow river! Furthermore, among my brother and cousins, it is those brought up in the north that is taller & stronger than us grown up in the south.