[mzkply]

Sure it does, and it has nothing to do with another country.

They will take 10 years teaching astronauts about everything from orbital dynamics to spacewalking to Siberian survival.

It's literally millions of dollars spent on one person, so you need to maximize the probability of success. It's why they go for perfectly healthy people, both physically and mentally. Can't have someone quickly out of breath, or someone who breaks down in a stressful situation.