She says “humankind” because she’s afraid to say “mankind”, because of women’s lib.
More properly she should speak of "H2O based lifeforms" to avoid any accusations of offensive or preferential terminology.
12 posted on 12/10/2011 12:02:12 PM PST by Iron Munro
("Don't pick a fight with an old man. If he is too old to fight, he'll just kill you." John Steinbeck)