I just took a look in Pete Seeger's book "Where Have All The Flowers Gone?" and he does indeed give the lyrics as adapted by Staughton Lynd (which is the version Joe quotes.) Pete says "Today I make so bold as to keep Alex's great three syllable title but amend the rest of the words".

I suppose we need to distinguish between a song referring to the neuter gender (which doesn't make sense in the context of this song) and a song being gender neutral (which does).

LFF