There is a price you have to pay to make a whole new planet your own. The choice of accessible celestial bodies is scarce, to say the least. A long-term colony, and by this a mean centuries and many locally born generations, will certainly uncover a large bunch of problems, and develop a number of adaptations, possibly including eventual genetic changes.
I had a similar reply to someone else: by the time we can adapt to live on Mars, decades away at best, traveling there will be the least of our worries. Glad to be proven wrong, of course.
Maybe we can try and terraform it in the meantime.
People would have bone density problems much sooner in life, as an example.