Complex sentence: Sergey Fesenko Jr. (also spelled as Sergiy or Serhiy, born June 5,1982) is a long-distance freestyle swimmer from Ukraine, whose father, Sergey Fesenko, was a gold medalist in the 200m butterfly at the 1980 Olympic Games in Moscow.
Split into simpler sentences: Sergey Fesenko Jr. (also spelled as Sergiy or Serhiy, born June 5,1982) is a long-distance freestyle swimmer from Ukraine. His father, Sergey Fesenko, Sr., won the gold medal in the 200m butterfly at the 1980 Olympic Games in Moscow.