It's only in the past few years, with increased exposure to discussion forums on the internet, that I have found out, there are a lot of people who believe that population explosion is a myth, and that there are a whole lot of benefits to having a huge population. Here's my take on it:
1) It should be obvious to anyone that the resources on this planet are not unlimited and that more people means less to go around. A lot of people would say that we are underuitilising our food production capabilities, or that there is an unequal distribution, and that fair and equitable distribution of resources would make sure that there is enough for everyone. This may be true for today. But what will happen when all the young people born today start having kids of their own. Wouldn't the population increase exponentially? Would you still have enough capacity to produce food for the population, say, 50 years later? Even if we keep aside the fact that humans are not the only species on this planet and the resources are not just for us to plunder, we still cannot continue to increase our numbers without regard for where the food, air and water are going to come from.
2) The situation of equitable distribution of resource is idealistic. The reality is of resource distribution being extremely skewed. Which leads to wars. With the advances in technology, wars are more devastating today than they have ever been in the past. Growing population only means more war, where people will suck out the resources from their own lands and then move on to other relatively unused areas. Don't we learn anything from history???
3) There is the idea of a large population giving a large labor base. For more than a hundred years now, we have steadily been decreasing our dependence on manual labor. We have technologies to farm huge tracts of land with a handful of people and so on. We had supposedly freed humans from manual toil to explore higher pursuits. But we still say that we need billions of people for the workforce. Yes, if you have a population of more than a billion, you will definitely have a few hundred thousand who have managed to fight their way to the top, having parents who could scrounge up enough resources to send them to school to learn English and other important languages like Java and C. But what about the majority of the billion people? They are still in the same illiterate state, subsisting on barely one meal a day. Now imagine there is a smaller number of people, so that there are greater chances of a student getting into an institution of tertiary education or of getting a job that lets him live at a level above subsistence. Wouldn't it be easier all around? Isn't producing a billion of a commodity to use only a few hundred thousand a bit wasteful? If people have fewer children, they can feed them better, so that they are be more healthy and more productive. The state could even afford to provide quality education to them for free, hence giving them better chances of earning a living.
4) The problem of a large set of elderly people is cited as a reason for not drastically controlling the population. If the elderly people are able to live healthy lives, the retirement age could well be extended and they could live productive lives, instead of having to be a "burden" on the young population. Fewer people would mean fewer patients to admit in hospitals, and more medication to go around for sick people, a higher propoportion of doctors to patients, better care for elderly and so on. If all the people can be involved in gainful labor in their youth, then they can save a sum of money to tide them over in their old age too. In any case, having been freed from manual labor, age is not really a restriction on the productivity of an individual.
All this seems like common sense to me. No experts have been quoted in the making of this post. This is all simply from my own observations. I would like to find out more abount how people can justify not controlling the population. I would hope that they would reply in a similar vein, though.