A leading US Baptist commentator has accused Bruce Jenner of embracing the ancient Christian heresy of gnosticism by transitioning into a woman.

Jenner, a reality TV star who won a gold medal in the decathlon at the 1976 Montreal Olympics, has said he remains both a Republican and a Christian. "I've always been more on the conservative side," he said on ABC last Friday night. He admitted, however: "I would sit in church and always wonder, 'In God's eyes, how does he see me?'"

Rusell Moore, president of the Ethics and Religious Liberty Commission of the Southern Baptist Convention, has warned against falling for the "cultural narrative" which he says is behind such changes.

In a post on his website titled: "What Should the Church Say to Bruce Jenner?" he describes how in the 1970s, Jenner seemed to have it all, and was such a popular Olympic star that he was reported to have been considered for both the roles of Superman and James Bond.

Now best known as the step-father on tv's Keeping Up with the Kardashians, Moore writes that Jenner is a symbol and a celebrity spokesperson for an entire mentality that sees gender as separate from biological identity.

"So is there a word from God to the transgender community? How should the church address the Bruce Jenner in your neighbourhood, who doesn't have the star power or the Malibu mansions but who has the same alienation of self?" he asks.

Arguing that Christians should not "laugh" at transgender people because they are not "freaks to be despised" Moore claims: "they feel alienated from their identities as men or women and are seeking a solution to that in self-display or in surgery or in pumping their bodies with the other sex's hormones."

He relates this to the fall of man, as told in Genesis.

"In a fallen universe, all of us are alienated, in some way, from who we were designed to be. That alienation manifests itself in different ways in different people."

He argues that the cultural narrative "is rooted in the ancient heresy of Gnosticism, with the idea that the 'real' self is separate from who one is as an embodied, material being. Body parts and chromosomal patterns are dispensable since the self is radically disconnected from the body, the psychic from the material."

Moore condemns "techno-utopian scientism" for helping propabate a belief that "tells us that we can transcend our limits, to become as gods."

Instead he argues for the Bible. "A biblical view of our place in the universe is quite different. We are not machines, to be reprogrammed at will; we are creatures."

Everyone is born alienated, he continues. "We don't need to fix what happened in our first birth; we need a new birth altogether."

Maleness and femaleness are part of biological design he concludes. "We will stand with conviction, even as we offer mercy. We've been called to keep in step with the Spirit, even if we can't always keep up with the Kardashians."