The impact of having a child has bothered me since having mine. The cartons of milk, the wasted clothing, the big boxes that his stuff came in, the nappies, the wet wipes… my recycling bin has gone from being taken out every three days to every day.

I heard about a scientist’s hypothesis to engineer humans to be smarter. His reason for doing this was simply that on average smarter people have fewer children. I guess he realises, as you say, that simply telling people to have fewer kids to save the environment would be ineffective. His solution sounds crazy – he also wants to bio engineer us to be shorter.