Over a lifetime, the risk is roughly 1 in 200 (0.5%). It is the 16th most common cancer in men. It accounts for less than 1% of cancer deaths in men (around 60 men died in 2012). Other animals
Testicular tumors occur also in other animals. In horses, these include interstitial cell tumors and teratomas. Typically, the former are found in older stallions (affected stallions may become extremely vicious, suggesting excessive production of androgen), and the latter are found in young horses and are large. References
External links

Ball Checker, self-exam app from the Testicular Cancer Society
Testicular Cancer – detailed guide from the American Cancer Society
Testicular Cancer – National Health Service information and resource page (UK)
Testicular cancer statistics from Cancer Research UK
Selenous acid can also be made directly by oxidizing elemental selenium with nitric acid:

  
    
      
        
          3
          
          Se
          +
          4
          
          
            HNO
            
              3
            
            
              
            
          
          +
          
            H
            
              2
            
            
              
            
          
          O
          ⟶
          3
          
          
            H
            
              2
            
            
              
            
          
          
            SeO
            
              3
            
            
              
            
          
          +
          4
          
          NO
        
      
    
    {\displaystyle {\ce {3 Se + 4 HNO3 + H2O -> 3 H2SeO3 + 4 NO}}}
  Unlike sulfur, which forms a stable trioxide, selenium trioxide is thermodynamically unstable and decomposes to the dioxide above 185 °C:

  
    
      
        
          2
          
          
            SeO
            
              3
            
            
              
            
          
          ⟶
          2
          
          
            SeO
            
              2
            
            
              
            
          
          +
          
            O
            
              2
            
            
              
            
          
        
      
    
    {\displaystyle {\ce {2 SeO3 -> 2 SeO2 + O2}}}
   (ΔH = −54 kJ/mol)Selenium trioxide is produced in the laboratory by the reaction of anhydrous potassium selenate (K2SeO4) and sulfur trioxide (SO3).Salts of selenous acid are called selenites.