space colonization is a fantasy from the era of rapidly growing population. now that the population is shrinking at near-extinction speed, what's the point of it? the Earth is not and will never be as inhospitable to us as dystopian sci-fi depicts. even Antarctica is a better target for colonization that Mars, where the gravity is wrong, the air is poison, and the soil is poison.
huh? what restrictions? China's one child policy was abandoned more than a decade ago, now replaced with "pls have children, as many as you like!" policy.
If you do'nt 'fix' earth why fixing up mars?
Nothing in the laws of physics prevent that. So at the very least, we know that it's not impossible.