Dirk Schnabel of the Charité Hospital Berlin works at the Institute for Experimental Paediatric Endocrinology. We talk to him about tall humans and the causes for growth.  DW-TV: Here in Germany I certainly get the feeling that the kids are getting bigger every year. Apparently the largest people in the world are the Dutch, Germany’s next door neighbors We've invited an expert from the renowned Charité Hospital here in Berlin to tell us a little more about why. DW-TV: Dr Dirk Schnabel, welcome to Tomorrow Today... you're an expert on hormone imbalances that lead to growth problems. What do you think is going on here – why are entire populations suddenly getting bigger? Dirk Schnabel: What are the main factors influencing final height? First of all, the genetic potential given by the parents. Then hormones, and health – ie no infections, good protein intake, good food quality – those are the factors that influence final height. DW-TV: How much of it is genetic, and how much is environment? Dirk Schnabel: There's a little bit of speculation about it but I think about 70-75% of the final height is affected by factors coming from the parents' genes. DW-TV: And the environmental factors are? Dirk Schnabel: Environmental factors are most determined by food intake and the quality of the food, and also health – no infections, no chronic diseases. DW-TV: Doctors can predict with a certain degree of certainty how big a child will grow to be? How do they do that? Dirk Schnabel: At the age of seven it might be good to look at an X-Ray of the left wrist, and at the calcification of the bones, and we look at the spaces between the bones named epiphysis and then we can make a prediction about the child's final height. DW-TV: Are there certain foods that promote growth? Growing up in the States, for example, they told you that if you wanted to get big and strong like the cartoon character Popeye, you had to eat all your spinach... What are the foods? Di...