• How cousin degree and removal work

  Count generations to the common ancestor; the smaller number sets the degree, the difference sets the removal.

• Full and half relatives

  What changes when only one ancestor is shared, and how the DNA figure halves.

• Great-aunt or first cousin twice removed?

  Why a grandparent's sibling is an aunt-line relative and a parent's first cousin is a cousin-line one.

• In-laws and step relatives

  Affinity versus blood: how marriage and step links extend the terms.

• Consanguinity and marriage law

  Civil-law and canon-law degree counting, and a general overview of cousin-marriage rules. Not legal advice.

• Kinship terms in other languages

  Languages that separate maternal and paternal relatives, and what English merges.

• How much DNA relatives share

  The coefficient of relationship, the theoretical average, and why real tests vary.

• How to start a family tree

  Begin with yourself, interview relatives, record sources.

• GEDCOM explained

  What the file format holds, what it drops, and how to move a tree between programs.

• Common ancestors and pedigree collapse

  Why you can share two ancestors with a cousin and what it does to the numbers.

• Naming conventions for removed cousins

  Why "once removed" is the same in both directions, and the alternatives people use.

• Keeping a family tree private

  What stays on your device, and how to back up and share a tree safely.

Looking for one relationship? Try the calculator or the list of terms.