panspermatist

from The Collaborative International Dictionary of English v.0.48

Panspermatist \Pan*sper"ma*tist\, Panspermist \Pan"sper`mist\,
   n. (Biol.)
   A believer in panspermy; one who rejects the theory of
   spontaneous generation; a biogenist.
   [1913 Webster]