I don’t understand how one kidney would affect a job?
There is no specific list of jobs people with one kidney cannot have. However, the American Academy of Pediatrics, American Academy of Family Physicians and the Medical Society of Sports Medicine have suggested that people with one kidney avoid sports that involve higher risks of heavy contact or collision. This includes boxing, field hockey, football, ice hockey, Lacrosse, martial arts, rodeo, soccer and wrestling. Also certain military regulations may not permit a person with one kidney to enter the service or to undertake certain military occupations.
Persons following certain occupations are peculiarly liable to Bright’s disease (nowadays called acute or chronic nephritis), which with only one kidney you would want to avoid. Exposure to lead or other toxins could put a person with only one kidney at greater risk than someone with two.
I would assume that jobs that involve situations similar to those found in high-impact sports or exposure to toxins (such as gasoline, gasoline-based paint spray, jet fuel, mineral turpentine, degreasing agents, toluene, or other solvents) that cause nephritis would be the ones to avoid. These would include many manufacturing jobs, painting, certain kinds of chemist and engineering positions, being a mechanic, being a forensic pathologist, or playing professional sports. Possibly it would be a limitation to a job in law enforcement.
Apparently, sometimes it becomes difficult to get insurance if you only have one kidney.
However, by and large, people with one kidney tend to do just fine. They may have a slightly greater risk of developing high blood pressure, and may need to be monitored more closely as they age, but typical one healthy kidney can easily do the job of two kidneys.