John P. Dehlin, the founder and host of a popular podcast for Mormons who question their faith, announced on Tuesday that a 15-member church disciplinary council had unanimously decided to excommunicate him for apostasy.

The Church of Jesus Christ of Latter-day Saints, better known as the Mormon Church, confirmed that he had been expelled and maintained that it had done so because Mr. Dehlin led members astray by publicly proclaiming his disbelief in Mormon scripture and basic doctrines. But Mr. Dehlin said the reason the church expelled him now, after years of monitoring his “Mormon Stories” podcast and Facebook page, was his outspoken advocacy for same-sex marriage and the ordination of women as priests.

Image Mr. Dehlin, an outspoken critic of the Mormon Church, arrived with his wife, Margi, at the hearing in North Logan, Utah, on Sunday. Credit... Rick Egan/The Salt Lake Tribune, via Associated Press

In an extraordinary step, Mr. Dehlin released to reporters what he said was a transcript of a recording he surreptitiously made of the confidential meeting last August in which his local church leaders laid out the grounds for disciplining him. The transcript shows that the church leaders were troubled that Mr. Dehlin had made statements on Facebook and in podcasts that questioned such things as the existence of God, the Mormon Church’s claim to be “the one true church” and whether the Book of Mormon and other church scriptures are true and historically accurate.