David Attenborough’s two children were born in the 50s I think when the world’s population was a fraction of what it is now. I don’t think he has suggested a one child policy, just made the point that population growth is a critical issue for all of us.
Right, but have they had children too? They are still causing damage, even though David Attenborough was not aware how bad things were at the time. Morally, he has a better defense and I suppose most people are saying 2 is just about ok, so he maybe wouldn't even need to defend himself today either. But the damage is the same.
I do not see the value in now punishing people for having larger families, which already exist as the damage is done now.
I definitely think that the tide is already turning and large families are no longer seen as aspirational in some areas (overpopulated areas, like where I live, in one of the most densely populated areas in the country). That is a good thing.
Focussing on children born 20, 15 or even 5 minutes ago, is about as useless as berating someone for any other decision they made some time ago. That long haul flight, that time you drove to the shop, that time you went on Atkins, bought a fridge full of meat, fell off the wagon, couldn't face it and threw it in the bin*.
Again though, I am in favour of smaller families being encouraged in some way and think 3+ is a bad idea.
*before anyone says it, yes, I know that children cause more damage to the planet than those things, however, they also potentially benefit society and the planet as well, so it is actually impossible to compare like for like. Even carbon footprint calculators tend to assign children their own footprint as they are separate human beings.