Don't short yourself on children which are your biological imperative (edit: unless you don't want kids either way) just because of false statment that Earth is overpopulated. The system is broken, industry is fucking all of us and when we would improve on those fields we could sustain even more people while simultaneously being more green. Also, population growth is steadily declining since the 60's and overall population number will soon start to plummet. It will cause problems down the line as population gets older and lives longer.