Which is why the ISS is populated by PhDs in their 40s? Of course you want the first colonists to not be sickly, but they won't need to be Olympic decathletes

Which is why the ISS is populated by PhDs in their 40s? Of course you want the first colonists to not be sickly, but they won't need to be Olympic decathletes in their 20s. Equipment for lifting heavy objects can be sent more cheaply than people (it can go slowly and doesn't need life support). I think for a venture like this maturity and patience is going to be more important than physical strength. There will be a lot of tedious tasks with long checklists that need to be followed near exactly to succeed. There will be a lot of disappointment and frustration when things fail or timelines slip. There will be the irritations of being stuck in a small social circle with a few people you intensely dislike but have to depend on for survival. Add in the fact that your sperm or eggs will probably get exposed to large doses of radiation until they figure out how to get to Mars faster, and it will be far less attractive to anyone who is planning to have kids someday.