Most genealogy software packages rely entirely on the computer to assign numbers to individuals in the database. Parents are then linked to the children on the basis of this number. Quinsept's Family Roots is one of those which operates this way. It is also one of those which allows you to include your own numbering system, as do most others. The Dollarhide program, which - as pointed out later - will generate a printout using the Register System, allows you to use your own numbering system and now supports a user-defined numbering system such as the Modified Henry (see earlier discussion). In fact, most genealogy software have options for user-defined fields.
M. O. Duke, author of the program Genealogy on Display, believes that "the only really valid numbering system is pure numeric: "Let the computer keep track of relationships and families within its own structure. Let it present the information in a format which we humans are accustomed to seeing, or would like to see. But, don't require that computers keep track of information in the way that we humans do." His program requires that every person get three numbers: (1) a unique serial number in the database, (2) his or her father's serial number, and (3) his or her mother's serial number. A fourth number is needed to link the person to his or her spouse! Other programs, because of the way they relate individuals within the database, require that individuals be entered in a certain way (e.g., in ascending or descending order or children right after parents).
ROOTS and Everyone's Family Tree (Dollarhide Systems) are two programs which will print out their databases in Register or Modified Register formats. The latter also will printout genealogies using a Modified Henry numbering system. Other programs, either have the built-in ability or have specially written utilities that allow Henry numbering system printouts. If these features are important to you, be sure to check their current availability before investing in a program.