In the mid 1980s, when I had my first child, it was in the face of dire apocalyptic predictions. The US was run by an apparent madman called Ronald Reagan. (Our idea of what constituted a madman running the US has of course been refined recently.) Reagan's polices and arms war with the USSR had led many people to believe nuclear annihilation was just a countdown away. In 1983, what was basically a filmed lecture on this theme by Australian doctor Helen Caldicott called If You Love This Planet won an Academy Award and scared the bejesus out of everyone.
Many people, myself and my wife included, worried about the wisdom of bringing a child into a world under such a threat. I'm glad we ultimately weren't deterred and I'm pretty sure my kids are too. The debate is now just an entry in the "What on Earth were we thinking?" chapter of our life stories.
Today that pattern is being repeated in the face of the considerably more real threat of climate change. Many people around the world are deciding not to have children, and they have a good case.
There are two aspects to this: one is the environmental threat represented by the little blighters themselves; the other is the ethics of bringing them into a world which is on a helter skelter rush to destruction.
A world with more children in it might be difficult to sustain; but a world with no more children in it would be guaranteed unsustainable.
No unborn children are going to complain that we did not give them life, but if everyone decided not to breed, humanity would disappear in fewer than 100 years anyway, according to Amy Kaler, a professor of social structure at the University of Alberta.
The insects and plants would happily take over in no time at all, and probably adjust to the new climate better than we could.
Some people have always been against breeding. The anti-natalist movement believes it's philosophically wrong to bring kids into a world of existential misery and pain. They've never really caught on, and they have the worst parties.
There have also always been people who have opted not to have children for personal reasons. There's is no arguing with that when it's a lifestyle decision and not dressed up as being in the public interest.
Certainly, children are much worse for the planet than single-use plastic bags. According to a study called "The Climate Mitigation Gap" published in Environmental Research Letters, not having a baby could save as much carbon per year as 73 people going vegetarian. They are equivalent to 58.6 tonnes of carbon emissions.
But the morality of bringing children into a world of environmental degradation is a different matter. What will their lives be like?
The planet almost certainly will get a lot worse before it gets better, but humans are tough and our drive to survive means we can accommodate ourselves to all sorts of conditions. Ultimately we need to have faith in ourselves and our potential.
To decide not to have children for the planet's sake is to give up on humanity. We need to believe that life will go on. That is how we live now: We all know we're going to die one day, possibly tomorrow, but that doesn't stop us making plans.
In fact, when it comes to finding a solution to climate change and working to make it happen, according to Josephine Ferorelli of lobby group Conceivable Future, children can help.
"For the most effective activists," says Ferorelli, "their reason for doing this work is because of their children."
That's because when we look at children, we don't see 58.6 tonnes of carbon. We see love.