Who are Goku's brothers?

Goku is only known to have one brother, named Raditz. It is questionable whether the name "Raditz" is a spoof on "Radish," since Saiyan names tend to be spoofs relating th vegetables ("Vegeta" being a direct spoof of "Vegetable" and "Kakarrot" possibly being a spoof of "Carrot" although that is disputable). Raditz came to Earth in the beginning of Dragon Ball Z and kidnapped Goku's four-year-old son, Gohan and threatened harm to Gohan unless Goku killed 100 humans by the next day.