Even as it shifts its policy on gay leaders, there are still millions of Americans today who do not meet one of the basic requirements to become a Boy Scout leader: those who does not hold religious beliefs.

Religion has always been at the center of the Boy Scouts, whose oath includes a pledge "To do my duty to God and my country." And although the Boy Scouts of America is closely tied to the Protestant-based YMCA, the organization describes itself as "absolutely nonsectarian" and welcomes all faiths.

Those with no faith are a different matter.

People who hold no religious beliefs are not eligible for membership in the Boy Scouts -- a policy which excludes a large and growing demographic. According to a recent Pew poll, nearly 23 percent of Americans do not identify themselves as religious.

"The Boy Scouts of America maintains that no member can grow into the best kind of citizen without recognizing an obligation to God," the Boy Scouts' Declaration of Religious Principles reads in the organization's bylaws.

READ: Religious groups react to Boy Scouts’ vote to drop ban on gay adults

The youth membership application says, "Only persons willing to subscribe to these precepts of the Declaration of Religious Principle and to the Bylaws and codes of the Boy Scouts of America shall be entitled to certificates of membership." In addition, the bylaws explicitly say only those accepting the religious principles can occupy a leadership position.

"Ultimately, it would be self-defeating for the Boy Scouts to forfeit the chance to spread Scouting skills and values among the population of people who identify as atheist, agnostic, or otherwise not religious," said Tom Krattenmaker, a writer specializing in religion in public life. "More and more youths are growing up in non-religious homes; why would the organization squander the opportunity to serve and influence these boys?"

While the 80-member board approved a resolution Monday (July 27) lifting the organization's blanket ban on gay adult leaders, it leaves it up to individual scout units to decide if they will permit gay leaders. "As of this vote, the Boy Scouts of America is an organization that is looking forward, not back," said Zach Wahls, 24, an Eagle Scout and executive director of Scouts for Equality.

But, in allowing individual units to continue to ban gay scout leaders, the Boy Scouts are actually taking a page out if its history, mirroring its handling of racial discrimination for much of the 20th century.

Although the organization never openly promoted segregation, it allowed local councils to decide their own policies on race. In the era of Jim Crow, that meant blacks faced an uphill climb in forming troops in the South - and those that were formed were segregated.

There was also opposition to blacks wearing the scout uniform. In one instance, Boy Scout officials in Richmond, Va. threatened to publicly burn scout uniforms if blacks were permitted to wear them, according to David I. Macleod, who wrote a book titled Building Character in the American Body. The book examined the scouts' early history.

The policy of permitting individual troops to discriminate based on race continued until 1974, when the NAACP sued after a 12-year-old African-American boy was denied a position as a patrol leader in a Mormon troop because he was black. At the time, Utah scout troops required that patrol leaders "must be a deacon's quorum president in the LDS Church."

Since blacks were barred from the priesthood in the Church of Jesus Christ of the Latter-day Saints, it effectively meant blacks could not become scout leaders in most Utah troops. The policy was changed and the suit was dropped.

The LDS Church has been one of the leading voices of opposition in the debate over gay scout leaders.

"The admission of openly gay leaders is inconsistent with the doctrines of the Church and what have traditionally been the values of the Boy Scouts of America," the Church said in an official statement following Monday's vote.

(William Cummings writes for USA Today. )