Killing is inhumane; Preventing treks over civil rights
However, even with preventing measures, the Earth's population would continue to grow and expand anyway.
We need to invest our money in urbanization and environmental co-operation, so we would be able to keep on growing until another planet was found to colonize.
If you were any smart chap worth his buck, you'd invest your capital into a privatized space company. If space transport and immigration emerges in the next 80 years, your investment could be worth millions.