An outline of all known descendants of a given individual, the register numbering system is designed to make it easier to track a line through multiple generations. Best used for final publication, the register numbering system is not the best choice for research in progress, as it is requires extensive renumbering when making additions or corrections. Another drawback of the register numbering system is that only blood-line descendants are assigned numbers (spouses do not receive a number).
The key to reading a register report is to understand its numbering system. The progenitor or primary individual is given the number 1. Each of his children is then numbered in sequential order by birth with lower-case Roman numerals (i, ii, iii, iv, etc.). If the birth order is not known, the children are usually listed in the most-likely order of birth. Children with known lines of descent included later in the report are also given an Arabic number (1, 2, 3, 4, etc.).
To look at it visually, here is the layout of a simplified register report:
Descendants of George Herbert Walker Bush
1. George Herbert Walker Bush, 41st President of the U.S., was born 12 June 1924 in Milton, Massachusetts. He married Barbara Pierce 06 January 1945 in Rye, New York, daughter of Marvin Pierce and Pauline Robinson. She was born 08 June 1925 in Rye, New York.
Children of George Bush and Barbara Pierce:
2. i George Walker Bush, b. 06 July 1946, New Haven, Connecticut
ii John (Jeb) Ellis Bush, b. 11 February 1953, Midland, Midland County, Texas
iii Neil Mallon Bush
iv Marvin Bush
v Robin Bush
vi Dorothy Bush
Second Generation:
2. George Walker Bush (George Herbert Walker1), 43rd President of the U.S., was born 06 July 1946 in New Haven, Connecticut. He married Laura Welch 1977 in Midland, Texas.
Children of George Walker Bush and Laura Welch:
i Barbara Bush, b. 1981
ii Jenna Bush, b. 1981

