I think. It is due to Genes.

I think there may be solid reason for this like eating ,activity,environment etc effect.

May be, But Genes I think are the main reason

There is also a roll of nutrition along with Genes for our body growth there was good diet in earlier times and all diet was pure and today's diet is adulterated. So I think this could also be a big reason for decreasing height.

It's not JEANS but GENES. I am sure, only Genes are responsible for the decrease in Size.

Thank you very much for showing me my mistake. I just improve it, by mistake it happened.

it's OK.

Peoples are decreasing in size day by day as compare to long years? reason..

Not sure from where you got this  idea? Is there any statistics to prove it or any scientific research paper published on the subject ? I have never come across any so far except the fact that size of the human brain is decreasing ..

I am not aware of this fact but I feel if at all size of human beings is decreasing gradually then, one main reason is that children are not regularly playing outdoor games. I stay in Delhi and I can see the upcoming generation having good height. Here, swimming, cycling, and other sports are very popular among the children and naturally, their growth is very good. 

The topic is misleading. 

I think this is also happening due to lack of physical activity. Now children are more engaged with mobile , video game, cartoons movies etc. Previously they play kabaddy, gulli danda , running etc.

Yes. The present day children spend more time in TV watching and other activities, that makes them dull.

I think, elders in the family must see, not to happen such waste activities.

I think people come in different sizes across the globe. Asian are short compared to other continent. So height depends on genes and geographic location. Geographic location decide your diet and lifestyle to a great extent. We still have mostly tall people in western region.

I think participation in sports is very important. It requires to move your body. Naturally, there is always some growth in one's body up to a certain age. For this every school should make sports compulsory and everyday workout is also very necessary.  

In fact, few months back I attended a workshop. A British educator was conducting the workshop. He said that if we see the evolutionary process, what is being used grows while what is not used diminishes. The Giraffe's long neck is a good example of use..stretching it to eat leaves. He said it on lighter notes that there might come a future where human beings might have a big head with small appendages protruding out of it as the coming generations are sitting all days in front of screen and using only their head. There is no physical activity to use hands and legs

I don't think that's true, my father was taller than my grandpa and I am taller than my father. I have no son but I am sure he would be taller than me.

I am of a firm belief that every child will pick up height if they get to swim, cycle, play basket ball or volley ball from a very young age. The movements and stretches help a child to grow taller.

suni51 wrote:

I don't think that's true, my father was taller than my grandpa and I am taller than my father. I have no son but I am sure he would be taller than me.

It will s the same in my family , all the children are taller than us and probably true of most other families too

By and large children today are growing taller than previous generations. With good nutrition especially at infant stages this is becoming possible.

The second thing is fast food which is not good on growing point of view. To grow well we need to eat good food and fruits like milk, apple, bananas, egg, seeds, nuts etc but fast food are being preferenced due to lack of time.