The know nothings
In the US about the time of the American Civil War there was a political movement called the 'Know Nothings'. I see it was just sleeping not dead.
Malthus wasn't wrong, he just was not able to predict the technological advances that enabled disaster to be postponed, note postponed not averted. Just remeber that the chances for the birth of a Hitler is just as likely as the supposed genius who will 'solve the problem for us all'.
wpelletier is correct, basic education of women in societies that have not traditionally done so is one of the best ways to reduce population as so many studies have shown. Family size goes down and health and economies grow.