Population.

> If the need arises and the environment can support a larger population
you can bet your bottom $ that even Highly-trained
> professionals, will breed like rabbits.

There are two schools of thought on this, I suppose. Savage, in
"Millennial Project", argues that since reproduction was rapid on the
American frontier, we'll see similar rates in space. I repeated this
argument on one of the space newsgroups. Someone else pointed out that
the average pioneer family in early America was a rural, farming family,
so they had family sizes consistent with that. He expected space
settlers to instead have family sizes consistent with urban
professionals. His argument was that couples do not determine family
size based on their assessment of the surrounding limits to growth (just
look at the 3rd world), and I have to say his argument persuaded me.

> Otherwise, we indeed have something to worry about - we will have to
fill the O'Neil habs with clones.

I remember getting into a debate with somebody on Usenet who started out
by begging the question that human reproduction was inadequate to
support space settlement, and then proposed artificial wombs and robotic
child rearing as the solution to the "problem". I disagreed with his
underlying premise, and suggested that immigration from Earth need not
be as difficult as he was imagining. Call me old-fashioned, but I found
his scenario chillingly inhuman, and advocated the standard way of
reproducing, which strikes me as perfectly adequate.

Hi,

Population worldwide is being controlled by some kind of intervention. If you remove the intervention the population will continue to climb (considering the existing medical knowledge) . The urge to reproduce is the next strongest urge after the urge for survival, in all life forms. Most educated people are aware that the world is overpopulated, so they voluntarily accept this intervention. Another very important factor is that a middle class family anywhere in the world, would face financial difficulties if they attempted to bring up more than two kids.

Even in India (we are a developing country) there is a belief that people have large families to support them in their old age. There is also a theory afloat that XYZ communities want to take over by increasing their population! Human beings pride themselves on their rationality, so they like to give rational sounding answers.

I have talked to a few persons who have large families in my village on this subject. The reason they cite is quite prosaic - they just did not have the information / knowledge on how to control their families! After all nature has contrived to make reproduction simple, even though the end product is many orders of magnitude more complex than a space shuttle. So I don't think clones will be needed. On the other hand proper ambience is required and educated people must feel there is some kind of a future in the environment where they abide. I remember reading somewhere that after the second world war, some couples did not want to have children because they did not see a future with all the nuclear stuff.

Regards
Selvaraj