When someone who will clearly make a great parent expresses guilt for having taken the liberty to procreate, there's something wrong with us.

In the modern world, and particularly among the middle classes and wealthy intelligentsia, we have become so ridden with guilt-complexes, so convinced of our own evil, that we can't even have babies anymore without indulging fashionable neuroses about it.

Giving life must be among the happiest things that can happen to anyone. When, recently, a friend expressed unmitigated joy at the prospect, it brought back to me how often one hears the opposite: people who are apologetic about adding to the world's population.

Even if we ignore the spiritual joy and emotional fulfilment a child can bring, and consider procreation purely as an economic act, should we really believe that it is a danger to humanity, to our prosperity, or to our environment?
This distressing notion is premised on a myth.

The myth is that a person is merely a mouth to feed; that people are merely living like parasites on an ever-dwindling supply of resources that will inevitably run out.

As a general rule, which holds true for the vast majority of people, nobody can consume more than they produce. While they are children, that production occurs on their behalf, but without enough production to sustain a life, few people can survive.

There are many reasons why population growth rates tend to be higher in poorer societies. One is that they risk a higher rate of infant mortality. This used to be true the world over, even among the rich. King Louis XIV of France had five children, of which only one survived. Queen Anne of England fell pregnant eighteen times. Her longest-surviving child died soon after his eleventh birthday. Tsar Peter the Great had 14 children, of which only three made it to 20, and only one past 30. Even in wealthy Britain, life expectancy only crept past 40 late in the 19th century.

A more important reason why poor people have more children is that they grasp the simple economic fact that on average, a person's potential production exceeds their likely consumption. They're an economic benefit to their family, their village, and their country throughout their lives.

The inevitable answer to this observation is that even if people can produce enough to sustain themselves, we're running out of resources.

The problem is, we're not. This can be reliably concluded from the fact that even if a particular resource were to become particularly scarce, the price mechanism unfailingly makes it worth our while to economise, or seek alternatives, or both.

Resource replacement has happened before, and will happen again, but more often, the opposite happens: improved productivity and new finds simply combines to match growing demand.

The challenge of improving farm productivity has been with us for most of the last century, as the world's population boomed as a result of growing prosperity, decreasing disease mortality, and improved living conditions. That challenge has been admirably met by people such as the late Norman Borlaug, who won a Nobel Peace Prize in 1970 for his spectacular successes in improving crop yields and farming methods in Latin America and Asia. Today, we feed a vastly expanded population on not much more land than was given over to agriculture in 1950.

There is much more that can be done – and is being done – to improve the productivity of existing farms, without significantly expanding the acreage needed to feed humanity by appropriating unspoilt natural environments. (That said, there are negative trends too: biofuels in particular place huge pressure on available arable land, raising food prices unnecessarily.)

Overall, however, despite the dire predictions made a few decades ago by eco-socialist academics such as Paul Ehrlich, using mathematical models of growth developed 200 years ago by Thomas Malthus, humanity is still feeding itself quite adequately today. There is no reason to believe that this has to end either soon, or catastrophically.

The first mistake inherent in these predictions is to presume that economics is a zero-sum game. This is the inherent flaw in ludicrous notions such as working out how many earths we'd need if everyone consumed like you or me. If the same calculation were made about production, would you find it reasonable to conclude that you produce several earths' worth of goods and services? No. You produce enough to purchase what you need to (or want to) consume, as does most everyone else.

The second is to ignore human ingenuity. As prosperity grows, people continually find new, better, or more efficient ways of doing things. While adjusting their lives to the reality of the environment around them, they still manage to produce prosperity growth in real terms. History is a resounding indictment of the economic philosophy that led groups such as the Club of Rome to conclude we'd all run out of resources and die.

Importantly, however, this kind of investment in the future requires optimism. We need to realise that despite the incessant laments of guilt and gloom, fashionable with prophets from Hosea to Al Gore, the reality is that living conditions have been getting better, and can continue to get better.

Pessimism is the great deterrent to investment, production and innovation, but the history of economic production does not justify pessimism.

Both in the rich and the poor world, people have continually produced more, improved life expectancy, reduced child mortality, lowered disease mortality, increased per capita calorie intake, and raised their real incomes – to name just a few indicators. By all means, pick others if you don't trust this selection, and test them against the wide array of statistics that are available to document historic and present quality of life.

The numbers do not say that everything is fine. Certainly, there are areas where malnutrition and disease remain rife, where structural unemployment remains a curse, where access to clean water remains elusive, where the burden on the environment remains high, where socialism continues to undermine prosperity growth, or where war and corruption continue to bedevil the progress of many.

But most indicators give us cause for optimism that things can and will continue to improve, just as they have done in the past, and especially in the last century or two.

It is exactly that optimism that is reflected in procreation of the species. Having children should be an expression of confidence that the future will be better than the past, and that it will be better still if your children can have a part in it.

This is why it is so heartbreaking to see mothers apologise for having children, as if the very act of creating life incurs mortal guilt. This is why it is odious to see children going to school only to be taught that they are a burden upon society and a disease upon the face of the earth.

No wonder people grow up to be so neurotic, if they have to make excuses for merely living. They don't, and neither do they need to make excuses for the children they bring into the world. There's something deeply wrong with a society that inculcates such awful guilt about life that the misanthropy extends even to its own babies.