 A subplot to this movie was to show that even in the 23rd century  humans hadnt totally shed their bigotry and prejudices.  James Doohan (qv) had a line about "that Klingon bitch", but  Nichelle Nichols (qv) refused to say it, in reference to the  Klingons "Yeah, but would you let your daughter marry one of them?"  The line was dropped.