An intriguing question that was recently asked by one of the scientists at my departmental retreat. Although simply stated I believe this is a rather important question that would be asked by several biologists . If you look deeply into the question it has two aspects to it.
The first one is the basic question of being born at all. Why does life have to propagate and why at all do species give rise to progeny. A simple answer would be that genetic information needs to be propagated and maintained and there is natural adaptation in response the changing environment which could lead to the "survival of the fittest". With increasing age and individual accumulates several harmful signals such as mutations, Telomere shortening, accumulation of Reactive Oxygen Species etc, just to mention a few of these defects, .that eventually lead to aberrant cellular programming and eventually death . But what if we could find ways to counteract these phenomenon? What id nature evolved to counteract these mechanisms? why do these exist at all? I earlier stated that being born or giving rise to healthy progeny could be a counter mechanism to adapt to the changing environments. But what changes the environment and I guess most of we know the answer to that, it's us the humans. So why did is nature not selecting against a species that could eventually be the cause of all chaos.
Speaking of evolution, just to bring up a point, I would not lose this opportunity to mention another aspect of evolution. There still exist several primitive species that have specific mechanisms that id acquired by a higher species might lead to the better survival. E.g. the long life span of turtles, the cancer fighting properties of snake venom etc. and we are still trying to understand why humans evolved in the first place and for how long could the species survive without disturbing the balance of nature.
What if we were able to create an individual with all the suitable characteristics to live for a 1000 years(or even more) would it still be necessary for life to propagate via reproduction and both? Would this individual not survive that long or could it be possible that such people cold actually have evolved and present amongst us without getting noticed..constantly moving... could they have witnessed or been Gods themselves because of the loss of aging and degeneration over years and the scientific knowledge lacking at the time, to understand this phenomenon.
Well, considering that the existing mechanism of reproduction and propagation is the most efficient and effective method evolved for persistence of life, I would then like to move on to the second part of my question as to why we are born young or for that matter any birth means the emergence of a new and young individual, but why young? To answer this I would like you to consider a continuously accumulating system. What is to stop the earth from getting overpopulated and eventual depletion of all natural resources? So I believe that being born young could have several reasons to it: (1) It has been shown experimentally that aging can be reversed or so to say the human cells could be reverted to a healthier and younger state. Being young means having fresh a fresh cellular milieu leading to less number of cells to begin with and therefore less DNA damage, mutation, telomere shortening etc., meaning a more healthier state over all. (2) There is also a time delay to sexual maturation.. again why?? probably to get the right body mass and size.. but could this also not be a mechanism to check on the population size allowing only a certain number of individuals to be present in the restricted availability of natural resources... but in any case the current population numbers tends to overrule this. Coming back to the question of being born young... If all of these arguments hold true then why is a young one not born earlier and has to undergo gestation for a certain amount of time inside the womb and why did nature select it this way and not anything else??
Well there is plenty of food for thought here and i assume that its time that scientists would want to give a second look into the biology of different organisms to decide for themselves alternate mechanisms that could have been present and lost during natural selection or advantageous characteristics of the biology of young organisms. After all we are still evolving and looking back in time could give us a glimpse of the future.. or at least we could predict and be prepared several possibilities to be ready for what evolution might bring our way in years to come.