Volunteers?

[Dixie]

Eleven women were clinging precariously to a wildly swinging rope suspended from a crumbling outcropping
on Mount Everest. Ten were blonde, one was a brunette.

As a group they decided that one of the party should let go. If that didn't happen the rope would break and everyone would perish. For an agonizing few moments no one volunteered.

Finally the brunette gave a truly touching speech saying she would sacrifice herself to save the lives of the others. All the blondes applauded.