According to a new poll, Americans trust commonly accepted scientific beliefs about cancer and vaccines, but are less convinced about scientific concepts about climate change, evolution and the Big Bang theory.

A recent Associated Press-GfK poll found that Americans are confident about scientific theories when they relate to health and genetics, but very skeptical when it comes to scientific research that doesn't have a great affect on their everyday lives.

The study shows that only 4 percent of Americans doubt that smoking causes cancer, while only 6 percent question whether mental illness is a medical condition that affects the brain. Only 8 percent of Americans are unsure about DNA and 15 percent question the safety of childhood vaccines, the AP poll revealed.

However, there's a big disparity among Americans when it comes to global warming since about four in 10 Americans are unsure or don't believe in it at all. The AP also discovered that 51 percent of Americans doubt the legitimacy of the Big Bang theory.

2013 Nobel Prize in medicine winner Randy Schekman of the University of California, Berkeley blames political figures and leaders as the reason why so many Americans doubt widely supported scientific theories. "Science ignorance is pervasive in our society and these attitudes are reinforced when some of our leaders are openly antagonistic to established facts," he said.

The poll also showed that political affiliation and faith are key factors in determining how an American views science. More Democrats than Republicans expressed confidence in evolution, the Big Bang, the age of the Earth and climate change. In addition, there was a sharp decline in confidence about these topics for people of faith, according to the poll. Similarly, Americans who regularly attend religious services and evangelical Christians had more doubts about scientific concepts which were contradictory to their faith.

"When you are putting up facts against faith, facts can't argue against faith," said 2012 Nobel Prize winning biochemistry professor Robert Lefkowitz of Duke University. "It makes sense now that science would have made no headway because faith is untestable," he told the AP, according to the New York Daily News.