Forbidden Fruit

Five decades later, it appears that Joseph Smith Jessop and his first wife also passed on the rare genetic disorder fumarase deficiency.

The stage was set for the appearance of the rare disease when their 12th child, Martha Jessop, married her second cousin, John Yeates Barlow, in 1923, according to LDS genealogy data and Colorado City historian Ben Bistline.

Peter Scanlon

Dr. Theodore Tarby says FLDS polygamists will continue producing children afflicted with severe physical and mental disorders.

Life Magazine

Polygamist patriarch Joseph Smith Jessop with his youngest daughter shortly before his death in September 1953.

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More About

• Theodore Tarby
• Joseph Smith Jessop
• Warren Jeffs
• Polygamy
• Religion

Like his father-in-law, John Y. Barlow became one of the towering patriarchs of the fundamentalist Mormon community and served as FLDS prophet from 1935 until his death in 1949.

The Barlow-Jessop marriage brought forth some of the major political and religious leaders of the community, including former Colorado City mayor Dan Barlow, police officer Sam Barlow, public school superintendent Alvin Barlow, teacher Louis Barlow, and civic leader Truman Barlow. All of these men have or had multiple wives and scores of children.

Fumarase deficiency began to manifest in the community when three sets of Joseph Smith Jessop and Martha Moore Yeates' great-grandchildren married each other. The three marriages between second cousins have produced at least eight children afflicted with fumarase deficiency, according to a report in the May 2000 Annals of Neurology(based on the study conducted by the group led by Tarby and Aleck), interviews with doctors treating the disease and anecdotal evidence gathered from the community.

The children afflicted with fumarase deficiency from these three marriages include the grandchildren of Dan Barlow and his brother, the late Louis Barlow, and Merill Jessop, a top aide to fugitive prophet Warren Jeffs. It is Merill Jessop who is overseeing construction of a massive FLDS temple in Eldorado, Texas, where many believe Prophet Jeffs plans to move his faithful eventually.

Dan Barlow, who has been excommunicated from the FLDS, and Merill Jessop could not be reached for comment. But Isaac Wyler, a former FLDS member who was excommunicated from the church last year, says he has firsthand knowledge of multiple fumarase deficiency children in each of the three families.

"I know this off the top of my head," Wyler says. "I know these people personally."

Medical experts say the incidence of the disorder will increase because the FLDS community is refusing to accept recommendations to reduce the likelihood of producing babies with fumarase deficiency. Tarby says he discussed the disease and its causes during a town meeting on November 18, 2004, that was attended by more than 100 FLDS members.

Tarby says he explained to the gathering at Town Hall in Colorado City that the only way to stop fumarase deficiency in the community is to abort fetuses that test positive for the disease and for the community to stop intermarriages between Barlows and Jessops, Barlows and Barlows and Jessops and Jessops.

Tarby says members of the community made it clear that neither choice was acceptable. Tarby recounts a conversation he had with a member of the Barlow clan in which he tried to explain why so much fumarase deficiency was occurring among Mormon polygamists.

"I said, 'You're married to somebody you're related to. That leads to problems.'

"The man's response was, 'Up here, we are all related,'" Tarby says. "They just don't worry about the effects of intermarriage."

Tarby says the disease could begin to show up in children at Warren Jeffs' new FLDS headquarters under construction on a 1,600-acre ranch outside of Eldorado. The FLDS already has moved several hundred men, women and children to the compound, many of whom very likely carry the fumarase deficiency gene.

The only long-term solution to the health crisis is for Barlows and Jessops to have children with spouses from outside the polygamist community.

"They have to outbreed," Aleck says.

But this is a very unlikely scenario for FLDS faithful, who practice a religious doctrine that requires men to be strictly obedient to religious leaders and requires women to give birth to as many children as possible to increase the sect's numbers.

"Who [from outside the fundamentalist Mormon religion] would want to go in there and join their population?" Aleck asks. "It's probably hard to recruit into that environment."

Indeed, even if an outsider wanted to join the FLDS community, such a person would not be welcome.

"They are discouraging any new blood," historian Bistline says. "They've got this idea that their blood is pure and that they want to keep it pure."

With no other options available, more FLDS families will be faced with the difficult burden of caring for children suffering with fumarase deficiency. Rather than take steps to avoid the problem, the FLDS loyalists may believe it is their duty to accept their fate.

"They think it is a test from God," says Wyler, who was born and raised in the FLDS before he was booted out.

And a terrible test it is.

Fumarase deficiency is caused by a lack of the fumarase enzyme, an essential component in a biological process called the Krebs cycle, which converts food into energy within each cell. Not enough of the fumarase enzyme can lead to severe mental retardation and physical deformities.

"The kids that I have seen have terrible seizure disorders and developmental delays," says Dr. Aleck. "They are functioning way below their chronological age."