It's a silly rule that serves no practical purpose.

Think about it....the Russian OC groups have guys from mixed ethnic backgrounds and the Russian OC groups are a lot more successful than Cosa Nostra.

Look at Joe Watts who had a Welsh father and a Italian mother and he could have easily have been a Gambino capo had he been made. Watts bought in tons of money for the Gambinos but because his father was Welsh suddenly he is unworthy.

Stupid.