Some people apparently think that the Red Rain is from a
Rust Fungus of some type.
Apparently, the tests which were run in 2003 were considered to be non-conclusive regarding the presence of DNA. More tests are currently under way.
The bottom line so far seems to be that nobody can say conclusively what the red rain is composed of, nor can anyone reliably identify the source.
About 50 tons of this stuff fell over a large area, and over a period of many weeks to months (in periodic events).
Mainstream scientists won't begin to back the theory of extraterrestrial orgin until more conclusive tests are done and a more detailed description of the material emerges.