The reason you're not ever living on Mars is that it has no magnetosphere. Good fucking luck surviving any length of time with constant ionising radiation slapping the shit out of your DNA. This fact alone should have shut down any discussion of feasibility about colonising Mars.
Although it does make the three-titted chick from Total Recall way more realistic.
Very true. There's also the issue of giving birth. Women would have to be spun around like salad in a spinner in order to simulate Earth gravity but I imagine that's a perk for Elon.