Hi VIckki, It (testicular cancer) well may be - genetic-- the important thing is to have him neuterd and a biopsy done on the effected testicle ASAP____!! With all hope it is a local cancer-- meaning excising it should be curative. Are the ferrets you mentioned related? Then it would strongly suggest a genetic beckground-- if they are not -- is there an injury that may have promoted inflammation and later an abnormal exhibition of the testi??? Manby questions, but until you actually run pathology -- you may not know the answers. Good luck-- we have seen this before in rescue ferrets! alicia [Posted in FML issue 2306]