I believe nutrition is the primary factor in determining height. Look at the Europeans, for generations their growth were stunted by poor diet. In fact, the average height of an Englishmen at around 1000 A.D. was 5' 4" ! And it was not until the 19th century when diet did improve that the European men became progressively taller, overcoming the 6-foot mark. So here's my take on other races' height, such as Asians. They have been known to be shorter, and often people associate that immediately with genes. But really, where is the direct proof that genes determine height? In fact, we have never been able to eliminate nutrition as a factor in height determination. The Asian diet tends to be more vegetarian, actually a whole lot vegetarian than the average Caucasian diet (just compare rice, noodles, dumplings with steak, hamburger, pizza, milk) And so, it makes sense that Asians are shorter, not really because of some genetic inheritance, but because of diet. In fact, Asians are becoming progressively taller from one generation to the next. Again, it makes sense, because diet today in Asia have become progressively protein-dominant. Still, however, rice still makes up a significant portion of intake in the life of an Asian, as opposed to cheese and milk. So on average, Asians are still shorter.

Heightman