By his own account, Nielsen has 21 wives - and 36 children.
His oldest wife is 13 years older than he is, and his youngest wife is 43 years younger - she's just 24.
His oldest child is 21 years old, and his youngest is a 6-month-old baby.
That's one of the longer, single-family genealogies uncovered in a CNN review of the "Bishop's List" - a series of documents listing the age, marital status, children and address of the members of the Yearning for Zion polygamist ranch in Eldorado, Texas.
The ranch is owned by the Fundamentalist Church of Jesus Christ of Latter-day Saints, a Mormon offshoot that practices polygamy.
The Bishop's List was found among nearly 1,000 boxes of paperwork taken from the ranch by investigators who are considering child-abuse charges against some of the sect members. Video Watch how the list details convoluted family trees »
Investigators don't believe there is a "bishop" on the ranch. Instead, they believe sect members take orders from the man they call their "prophet"- convicted polygamist Warren Jeffs. Jeffs is in prison for forcing a 14-year-old girl to marry her 19-year-old cousin.
Jeffs was convicted last year in Utah on two counts of being an accomplice to rape, charges related to the marriage. Jeffs also faces trial in Arizona on charges of sexual conduct with a minor, incest and conspiracy.
Investigators say Jeffs still exerts control from prison through one of the men on the ranch, Merle Jessop. One of Jessop's wives is a former sect member, Carolyn Jessop, who left a polygamist compound and later wrote a book about her experience, called "Escape."
Last week, attorneys for the sect argued against a court review of the documents, claiming the documents should remain private under First Amendment rights to freedom of speech and association.
Judge Barbara Walther disagreed, saying the documents must be examined to try to find possible medical records of the sect children.
The Bishop's List also reveals other interesting details.
Most of the documents list the members' address as "R 17" - shorthand for the Yearning for Zion Ranch.
But on at least one family's document - the Jacob H. Johnson family - the address for Jacob's 22-year-old wife and infant daughter is listed as a "house of hiding."
Investigators have not revealed where or what kind of house that might be. Also, some sect members have refused to tell investigators - or said they don't know - how old they are.
Yet the documents in the Bishop's List seem to suggest that sect members do know their ages, and the ages of their children. Again, in the Johnson family record, one wife is listed as being "almost 28" while another is listed as being "almost 22."
The ages of the wives and their children are critical to investigators, who believe that underage girls were routinely married and forced to have sex with older men.
No formal criminal charges have been filed in the case. The next court hearing regarding the state's custody of 463 sect children is set for later this month.
The sheer number of children has created confusion between state officials and FLDS families and their attorneys, many of whom say their clients don't know where their children have been placed.
