1. Everyone can have one kid and we will merely double the amount of humans. This is because it takes 2 persons to produce one kid. And the infinite series 1/2

1. Everyone can have one kid and we will merely double the amount of humans. This is because it takes 2 persons to produce one kid. And the infinite series 1/2 + 1/4 + 1/8.... sums up to 1.