DECATUR, Ga. — The 80-year-old leader of a suburban Atlanta megachurch is at the center of a sex scandal of biblical dimensions: He slept with his brother’s wife and fathered a child by her.

Members of Archbishop Earl Paulk’s family stood at the pulpit of the Cathedral of the Holy Spirit at Chapel Hill Harvester Church a few Sundays ago and revealed the secret exposed by a recent court-ordered paternity test.

In truth, this is not the first — or even the second — sex scandal to engulf Paulk and the independent, charismatic church. But this time, he could be in trouble with the law for lying under oath about the affair.

The living proof of that lie is 34-year-old D.E. Paulk, who for years was known publicly as Earl Paulk’s nephew.

“I am so very sorry for the collateral damage it’s caused our family and the families hurt by the removing of the veil that hid our humanity and our sinfulness,” said D.E. Paulk, who received the mantle of head pastor a year and a half ago.

D.E. Paulk said he did not learn the secret of his parentage until the paternity test. “I was disappointed, and I was surprised,” he said.

Earl Paulk, his brother, Don, and his sister-in-law, Clariece, did not return calls for comment.

A judge ordered the test at the request of the Cobb County district attorney’s office and the Georgia Bureau of Investigation, which are investigating Earl Paulk for possible perjury and false-swearing charges stemming from a lawsuit.

The archbishop, his brother and the church are being sued by former church employee Mona Brewer, who says Earl Paulk manipulated her into an affair from 1989 to 2003 by telling her it was her only path to salvation. Earl Paulk admitted to the affair in front of the church last January.

In a 2006 deposition stemming from the lawsuit, the archbishop said under oath that the only woman he had ever had sex with outside of his marriage was Brewer. But the paternity test said otherwise.

So far no charges have been filed against Earl Paulk. District Attorney Pat Head and GBI spokesman John Bankhead would not comment.

The shocking results of the paternity test are speeding up a transformation already under way in the church after more than a decade of sex scandals and lawsuits involving the Paulks, D.E. Paulk said.

“It was a necessary evil to bring us back to a God-consciousness,” said the younger Paulk, explaining that the church had become too personality-driven and prone to pastor worship.

The flashy megachurch began in 1960 with just a few dozen members in the Little Five Points neighborhood of Atlanta. Now, it is in the suburbs on a 100-acre expanse, a collection of buildings surrounding a neo-Gothic cathedral.

For years the church was at the forefront of many social movements — admitting black members in the 1960s, ordaining women and opening its doors to gays.

At its peak in the early 1990s, it claimed about 10,000 members and 24 pastors and was a media powerhouse. By soliciting tithes of 10 percent from each member’s income, the church was able to build a Bible college, two schools, a worldwide TV ministry and a $12 million sanctuary the size of a fortress.

Today, though, membership is down to about 1,500, the church has 18 pastors, most of them volunteers, and the Bible college and TV ministry have shuttered — a downturn blamed largely on complaints about the alleged sexual transgressions of the elder Paulks.

In 1992, a church member claimed she was pressured into a sexual relationship with Don Paulk. Other women also claimed they had been coerced into sex with Earl Paulk and other members of the church’s administration.

The church countered with a $24 million libel suit against seven former church members. The lawsuit was later dropped.

Jan Royston, who left the church in 1992, started an online support group for former members to discuss their crushed faith and hurt feelings.

“This is a cult. And you escape from a cult,” she said. “We all escaped.”

These days, Earl Paulk has a much-reduced role at the cathedral, giving 10-minute lectures as part of Sunday morning worship each week.

“My uncle is 100 percent guilty, but his accusers are guilty as well,” D.E. Paulk said, declining to talk further about the lawsuits.