Though eight in ten Americans say they believe in God, only about three in five say they are "absolutely certain" God exists, a new poll shows.

A poll by Harris Interactive of over 2,000 adults found that 59 percent of Americans are "absolutely certain" and 15 percent are "somewhat certain" that there is a God.

Those over the age of 40, in the South, or who are female are most likely to be absolutely certain compared to 25- to 29-year-olds, those who live in the East and males.

Among Americans with religious affiliation, born again Christians (87 percent) and Protestants (76 percent) are most likely to express absolute certainty.

Thirteen percent of Americans believe there is no God, with seven percent saying they are absolutely certain.

The Harris poll found no consensus on the gender of God. Thirty-eight percent of Americans say God is male, 34 percent say neither male nor female, and 10 percent say both male and female. Among Christians, 55 percent of Protestants and 56 percent of born again Christians say God is male.

Americans are also split on how much God controls the earth. Forty-three percent say God observes but does not control what happens on earth while 30 percent say God controls what happens. Thirty-five percent of born again Christians believe God just observes while 59 percent believe God has control over what happens on earth.

In other findings, about seven in ten Americans say they believe in miracles, heaven, that Jesus is God or the Son of God, the survival of the soul after death and in the resurrection of Jesus.

Three in five adults believe in hell, the virgin birth of Jesus, and the devil.

Only 45 percent of adults believe in Darwin's theory of evolution and 40 percent believe in creationism.

Among born again Christians, 92 percent believe in the virgin birth, 91 percent believe in the survival of the soul, 89 percent believe in hell and the devil, 68 percent believe in creationism, and 16 percent believe in evolution.

The results are based on a survey conducted online Nov. 2 and 11, among adults aged 18 and over.