RECENTLY I attended a conference where one of the speakers, a young woman, told us that she, like a number of her friends, was choosing not to have children because of the impact on the environment.

Aside from this declaration being irrelevant to her topic (I wondered why she felt a need to signal her virtue in this way), it made me sad to think that so many young women – and I gather this attitude is increasingly common – are choosing to deprive themselves of one of life’s great experiences and joys.

It is doubly sad when I think of the number of couples I know who have struggled to have children of their own.

I just hope she doesn’t come to regret it – when she reaches her dotage, perhaps, and finds, by choice and not misfortune, she has no family to brighten it.

We might also wonder why those like her who refrain from having children for environmental reasons don’t instead adopt children, whose environmental impact is already costed in. Might their selfless concern for the environment actually be a front for something more self-regarding, such as their career and care-free lifestyle?

And who, we might ask, do they expect to look after them in their old age? The state, of course – staffed and funded by other people’s children. And by immigrants – for such people typically hail from the same political wing that favours open borders.

It’s an odd set-up, when you think about it – the outsourcing of baby-making. The thought, presumably, is that there are already enough people in the world, so rather than having children of our own, let’s import people from elsewhere. Short-sighted, some might say, given that immigrants also grow old and need looking after. And can we really expect our culture to survive such a radical change of personnel?

Personally – and call me old-fashioned – I believe our duty is to take responsibility not to avoid it. Which means helping to conserve your family and community, to nurture the next generation, not annihilate it.

But it’s the outsourcers who appear to be winning the argument at the moment. Britain’s birth rate as of 2017 sits at a dismal 1.7 children per woman, well below the replacement rate of 2.1, and that’s despite a boost from baby-friendly immigrant groups. Other European countries are at similar levels or lower – the EU average is 1.6 – as are some Asian countries such as South Korea (1.0) and Japan (1.4).

What is driving these historically low birth rates? A tangled nexus of cultural and economic factors is responsible.

The economic drivers include: the survival rate of children; the level of family income and especially the male wage; expectations around personal spending (such as number of foreign holidays) and spending on each child (which complicates the relationship with family income); and the support provided by the state and wider society to families including education, healthcare, childcare and income support. Worries about the future of the planet also play a part, as we have seen.

The cultural drivers of birth rates include the marriage culture of the society, such as: the sense that marriage is a basic moral duty; the average age at marriage (itself influenced by economic and cultural factors); the availability of sex outside marriage and the strength of the sexual urge; the attitudes of men and women to making themselves attractive to one another; and the security of marriage and the equity of divorce.

Cultural drivers also include the fertility culture of the society, such as: the availability of and attitudes towards birth prevention methods (contraception and abortion); attitudes to gender roles and the extent to which women desire to work and pursue careers; the age of women at first child; and the society’s overall socio-moral vision and the place of child-rearing and generational renewal within it.

In influencing these factors governments and others have a number of levers at their disposal. They can, for example, increase help to families through income support, childcare and healthcare – the favoured levers of the Left. They can strengthen and promote marriage (including through the tax system), discourage divorce and make it fairer, and reinforce traditional values around sex – the conservative’s home territory. They can choose policies which prioritise the male wage and encourage women to consider a traditional homemaker role – though these are unlikely to play well with feminists. They can promote alternatives to abortion and foster a social vision in which generational renewal is a central component.

Not all of these measures will have equal impact, some will be controversial, but all will help. A number of Eastern European countries have been running with pro-natal policies for a few years now and have seen some improvements, though at this (still early) stage they are yet to break through the replacement threshold.

There is no magic bullet to solve the demographic crisis of developed nations. A prosperous economy and a welfare state rely on maintaining populations with a healthy proportion at working age. Immigration is not an effective solution in the long term and brings with it social and economic challenges of its own.

It may not be wise to keep expanding the human population, but neither does it work practically or economically to shrink it. Governments need to get a lot more serious about facing up to their countries’ demographic problems. This means kicking their addiction to immigrant labour and exploring better ways of securing their country’s future from within their own populations.