>>name(PK),mother,father,oldestchild,nextoldersibling,nextyoungersibling,sex,[personal info]
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>
>You got it. YOu should only have to trace nuclear family realtionships, because all others can be derived from these. ie, an uncle is a father's brother. So to handle all cases, you would only really have to have 5 relationships: Mother, Father, Child, Sibling, Spouse.
>

Upon thinking about this more, you shouldn't even need a Child or Sibling relationship, because this data can be derived from the Mother and Father fields. For example, to find all of my bothers and sisters, and half brotherd and sisters, I simply find all of the people who share on or both of my parents.

To find all of my children, I only find all the records who consider me their father.

That's down to 3 relational fields in the people table.