It is impossible for a species to be entirely male, because males are merely females' way of inseminating other females. There are, however, a few species that are entirely female (parthenogenetic): some lizards, and quite a lot of rotifers. The lizards are an evolutionary dead end, but the rotifers, it seems, are not. For some biochemical speculations on why we can't get away with that, see www.mcb.harvard.edu/meselson.

--- Joe Fineman    joe_f@verizon.net

||: Suck, squeeze, bang, blow. Internal combustion makes it go. :||