there could be also genetic aspect of this, as height is a polygenic trait. It means, that different genes in different locations could affect this trait.

Therefore, globalization could also play a role in this aspect. If earlier populations with their specific genes of height were separated and therefore mean height was the same (as genes were near the same). But when people starts to move due to the wars, technical progress etc. different types of genes that affects the height starts to admix in their children. After several generations these genes can accumulate in one individual. May it be something like a heterosis effect that drives increase of a mean height in human populations...

"there could be also genetic aspect of this, as height is a polygenic trait"

This is covered by the pre-conception category. The genes are the encapsulation of all previous environments as shaped by evolution. Even geneticists are adamant that the recent secular height increase could not have been due to evolution acting on random mutations. Agreed, but they have overlooked a genomic explanation -- massive dumping of unfit genomes during periods of large infant mortality. Heterosis does not explain IQ increases.

IQ is something that is related with "standard" from point of view of modern human. But how much knowledge's about living in the wild we are loosing? - no one has counted as no one knows how to count this. Since we have many more time and opportunities to deal with intelligence-it grows.

The same situation with genetics still unknown how much genes/mutations/interactions inside genome are involved in the trait determination. I am not talking about interactions between genome and environment- it is still a huge black box for scientists.

Geneticists have counted only classical mutations inside the genes (2% of the whole genome), but area between genes also react to the environment and we just couldn't follow all this taking into an account generations or even populations. We just have little knowledge's about whole genome and all the processes inside organism, therefore we can say it is genetics, but we can't explain and prove this exhaustively with numbers.

Selection on this trait also exist, then we should talk about social and psychological aspect of the question.

Height is driven primarily by more calorie rich diets. In Japan a similar increase in height was noted after WW2. I remember reading that the average Japanese male height increased almost 5 inches in the generations after the war. Clearly this is not due to genetics, since the japanese are a fairly insulated population.

" Height is driven primarily by more calorie rich diets. In Japan a similar increase in height was noted after WW2...the average Japanese male height increased almost 5 inches."

In which case, there should have been no increase in height of 1y olds, with the maximum increase in young adults. But is this what has happened in Japan and elsewhere?

Ethnic group has not the same meaning as genetic population. Population is smaller. I don't know about Japan, but after II WW there was big starvation at least in Europe. Of curse, things like diet plays role and it is environment, but aspect of genetic nobody can deny.

Here in Israel we do not observe changes in average height of males and females during the last two decades.

It seems height as reached a plateau, on the other hand weight did not...

"Height is driven primarily by more calorie rich diets."

"Here in Israel we do not observe changes in average height of males and females during the last two decades."

A fatal blow for the nutrition theory, and indeed any other theories reliant on increasing standards of living.

It seems that height is influenced by diet and other factors to a certain extent. But it seems the height is influenced until one reaches a certain availability of nutrients and calories, and from there on we may be heavier but not taller....

Anthony, sorry but just because there is a limit to what nutrition can do does not mean it is irrelevant. The Israeli example is NOT a fatal blow at all. Height has increased in most countries during the 20th century but clearly we cannot grow indefinitely. You logic is seriously flawed. The allele frequencies have not changed very much , so clearly this is not genetics at work.

As I wrote earlier, there is a limit to the extent that height is affected by nutrition.

We have probably reached it. So now we grow in weight.

"The allele frequencies have not changed very much , so clearly this is not genetics at work."

If by this you mean the process of new mutations and the differential shaping of these by the environment, ie natural selection, then I agree. But you have overlooked a powerful genomic mechanism. When infant mortality was very high, infants from less successful (and shorter) mothers died in droves, eliminating less fit genomes (ie not individual genes) from the overall gene pool. As IM has fallen in the developed world, this positive feedback process has stopped, and height (and IQ) are no longer increasing here.

"there is a limit to the extent that height is affected by nutrition. We have probably reached it. So now we grow in weight."

So, more nutrition now increases horizontal growth but not vertical growth. This makes no sort of sense to me. Saying there is a limit is an observation, not an explanation.

"clearly we cannot grow indefinitely."

Not clear to me, I'm afraid. Perhaps someone more familiar with the GM or selective breeding literature can comment.

The TV is now full of programs dealing with the enormously obese. There is no limit in sight for the weight of the obese.

I am afraid we started mixing weight with height.

I am not convinced both are affected the same way by nutrition.

Definitely will look into the subject further.