I have heard some atheists use the theory of evolution to disprove god and falsify religion on the odd occasion. They probably are not well versed in philosophical polemics and prefer to stay in their area of expertise of biology and science. Plenty of scientists do actually use physics (of which gravity is an integral part) to disprove god too. In fact almost any discipline in science can be dragged over to the god/no god debate. I tend to think that if the believer says that there is a supernatural god, science cannot and should not tackle that idea because it is outside their 'jurisdiction' (I’m unsure of this term in this context but it seemed to fit well enough, disregard it if you like). However, if that believer then states that events such as miracles, healing or other phenomena have occurred then, as I have said somewhere before, they have just entered the scientific ball game. Once in this game these statements and events must withstand the test of science. If they do they can be verified as to be plausible, if not then the believer must reject them as false. Either way the believer cannot claim the 'supernatural' immunity of un-testability if the event happened in the natural world.
Divorcing evolution from religion was done 150 years ago. Today the only people wanting to make religion merge back with science are creationists and their step-child ID (Intelligent Design). These people are saying that their particular view of the first book of the bible, if read literally and in their specific way, contradicts the theory of an old earth and the larger idea of evolution, and for this reason they reject evolution. They do not use evidence. They do not use science. They only use biblical and apologetic arguments to form their idea. What science they do use is false, misrepresented, or out of date. The only way they get a nose in to people’s minds is the fact that in America (where creationism is the most heavily adopted) the level of basic science education is abysmally low. Many people soak up sciencey sounding ideas and do not posses the requisite tools to see the lies or chicanery behind the fluff. If anyone should be castigated for trying to instigate a war between science and religion it is these people.