"That would be insane," said Robert Zubrin, president of the Mars Society in Lakewood, Colorado. "If thats the case, we need to start action immediately to shut down on Earth chlorination plants, medical schools, anti-biotic factories and stop the production of mouthwash," he told SPACE.com.

"First of all, there is no life on the martian surface...there cant be," Zubrin said. Devoid of water on its topside, Mars surface is saturated by life-killing ultraviolet radiation and covered with a dusty, peroxide-laden covering, he said.

Zubrin said that if life exists on Mars today, it is subsurface, within underground water tables on the Red Planet. "We could go to Mars and take our entire nuclear arsenal there, bomb the surface, and that would not impact it at all. But going to Mars with people would allow you to set up drilling rigs, access the underground, and try to get samples of that life for scientific study," he said.

"First, I think if we find life on Mars, we should go and study it. Secondly, that planets potential usefulness for humanity as a future home is clear. We accomplish none of those objectives if we stay away. To say that millions of people from Earth cannot have a planet of refuge from persecution or a planet of opportunity, to have those dreams denied because esthetically it is pleasing that native martian bacteria are left un-intruded upon...thats just crazy. That is an esthetic position, not an ethical position," Zubrin said.

Stumbling into martian eco-niches, just right for life, however, may send a signal back to Earth that would evoke a go-slow response from society-at-large.

"There is no policy on what to do if and when we find life on Mars," said Margaret Race, an ecologist with the SETI Institute, Mountain View, California. There are "rules of the heavens" adopted by scientists that sweep the skies in a radio signal Search for Extraterrestrial Intelligence (SETI), she said.

"If a signal is heard, the operational response is to verify, consult, announce and then stop. There is no policy for exobiology type life," Race told SPACE.com. From a scientific perspective, decisions are now based on not messing up the science. Look for life, do it carefully and share the information, she said.

But decisions today are also being based on a very Earth-centric view, Race said, which touts that we have a manifest destiny to go there ... that "they" are only bacteria. "The question really comes down to, is it martian? If they are truly martian, by definition, they are rare and endangered," she said.

What to do next with a Mars life form find would grow to involve societal and ethical issue experts, and others, Race said. "I dont know if, in the end, that would stop or limit human exploration."

John Rummel, Planetary Protection Officer at NASA headquarters, senses that finding life on Mars would spark a go-slow approach. "We need to be prudent. We would like to know what were getting into before we immerse ourselves up to our neck," he said.

Rummel said that locating life on Mars -- whether or not it is related to Earth life -- is one of the most amazing discoveries that could be made in biological science. "To prejudge that we would somehow write that off because theres some people who want to go to Mars and wallow around in dust...I dont think thats a good idea," Rummel said.

Ultimately, however, it may require humans on-site to search out, find and best determine how martian life forms function, Rummel said. Such future on-the-spot studies by astronauts would be greatly assisted by first bringing back to Earth robotic grab samples of martian rock and soil, a plan that NASA hopes to put in place before decades end.

Penny Boston, a research biologist specializing in Mars life at Complex Systems Research, Inc. in Niwot, Colorado, waves a cautionary flag in the search for life on Mars. She said "the opportunity to make a definitive identification of life on Mars -- bacterial-type life -- is of such overwhelming importance that compromising the study by sending humans as if nothing had happened, is an inexcusable idea."

Boston said, however, that a human research presence on location is essential to adequately study any such life on Mars. The biological value of samples shipped back to Earth "will always be suspect," she said.

For Boston, there are two possibilities that arise, given life on Mars: Does Earth life come from Mars, or did it originate on Earth? "The only hope for solving this problem is scrupulously careful analysis of the organisms with no possibility of compromise by contaminating human-associated bacteria," she said.

"This does not mean a permanent moratorium on humans on Mars. It does necessitate additional caution," said Boston.

"Screwing up will be irreversible," she warned.