Cross-Contamination Concern

There has been some recent concern regarding Mars and Earth cross-contaminating each other. What with our fascination and desired exploration of Mars, some people have voiced concern about microbes possibly brought back from Mars that could contaminate or harm existing life on Earth. Microbes already exist on Earth that cause great harm (ex. Ebola). What's scary about microbes from Mars is that we don't know the nature of the diseases. The reality of this possibility is unknown; I'm not positive that we really need to be worrying about microbes from Mars infecting Earth with diseases.

What seems to be of more concern for people is that our microbes might contaminate Mars rather than vice versa. The perspective of the author of the article is that cross-contamination has been occurring for billions of years. Comets of all sorts carry bits of microbial life on them. Therefore it is possible that life on Earth occurred in the first place because of a rouge comet from Mars that had microbes on it colliding with Earth.

If this is accurate (and I'm not even sure that it is), do we really even need to worry about cross-contamination? Could it potentially be helpful in intentionally starting life on Mars? Maybe the whole thing a non-issue if the chances of microbes landing on Earth on slim to begin with.

http://www.naturalnews.com/009047.html