If my cousin gets married am I now related to his new wife's immediate family. Would I be related to his new wife's brother or sister?

  • 2
    Hello, Kent, and welcome to genealogy.Se. can you give us a little context on your question, such as why you need to know? Thanks.
    – user104
    Commented Dec 1, 2013 at 18:20
  • So what would a cousin of ones SIBLING'S husband be? That would seem to be a cousin-in-law to my SIBLING, and since any cousin of my sibling would be a cousin to me also, wouldn't my sibling's 'cousin-in-law' also be my cousin-in-law?
    – user3815
    Commented Feb 27, 2015 at 5:17
  • 1
    Hi @d541, welcome to G&FH.SE ! Stack Exchange focuses on questions and andswers to questions. Your post is not an answer, so don't be alarmed if your post gets converted to a comment. You can find out more about our format by taking the tour and looking in the help center. Also see Seeking English term for relationship between two members of extended family?
    – Jan Murphy
    Commented Feb 27, 2015 at 5:25

3 Answers 3


The apparently simple expression related to actually hides an extra-ordinary amount of complexity. It might refer to any or all of the following

  • a blood relationship (now better described as a genetic relationship)
  • a legal relationship
  • a cultural or customary relationship

In particular communities, each of these could impose familial obligations or limitations (taboos).

Genetic relationship

The fact that your cousin marries does not create any new relationship (that did not exist before). That appended caveat is necessary because it is possible that a search back through 10, 20 or more generations will show that you and the bride's family have a common ancestor (or two). We all have many more related family than we are aware of.

Legal relationship

Obviously these vary across jurisdictions and time, but if we adopt an anglo-centric world view then we can confidently say that the Anglican (Episcopalean) Church sees no legal impediment to you marrying a sibling of your cousin's wife (subject to you meeting the gender requirements). You do not have a prohibited degree of affinity.

Customary relationship

In many cultures, this is a rich area for linguistic study. In the anglo-saxon world we are largely restricted to the term cousin. Its strict usage refers to someone with whom we share a common ancestor although the word is now used to serve many other purposes (such as the all-to-common references to cousins-in-law).

Your questions takes on new meaning when (if) the happy couple have children. Your cousin's son is also your cousin (although one degree removed) and so the bride to whom you are now unrelated will become the mother of your (new) cousin. Try not to think about what happens if she were to ask you to be the child's godparent.


None of this technical discussion is of much practical assistance when you are all present at family (or is that, families) gatherings and wondering what to call people. Feel free to adopt whatever usage is acceptable to both parties and avoids confusion. Just do not say it in front of a genealogist, we tend to be a bit possessive of our vocabulary.


No, you would not - the term "cousin-in-law" is often used to refer to either your cousin's spouse, or your spouse's cousin(s) (although the more correct term would be "cousin by marriage"). Neither legal nor anthropological/sociological affinity recognizes relationships more distant than that:


It's common, at least in some parts of the U.S., to refer to people being "related by marriage" as though the "in-law" affinity propagated indefinitely, but there's no basis for it other than popular imagination.

  • One of the links on the disambiguation page points to Affinity (law) which has an example relevant to the OP's question: ... the spouse of a cousin may not be called a relation at all or may be referenced as a "cousin by marriage".
    – User5910
    Commented Jan 6, 2021 at 3:44
  • Updated to reflect changes to the Wikipedia source
    – cleaverkin
    Commented Jan 7, 2021 at 5:14

Yes, you would be related in-law (where we get the term "in-laws"). However, you would not be related by blood.

You could consider his/her spouse to be your cousin-in-law. However, this term is rather inaccurate because it could also describe your spouse's cousin.

  • Technically, this is true, but for legal purposes (which are not within this site's scope!), the definition of 'related by marriage' may differ from jurisdiction to jurisdiction.
    – user104
    Commented Dec 1, 2013 at 18:20
  • True. I wasn't thinking about legalities.
    – Luke_0
    Commented Dec 1, 2013 at 18:54
  • Who is considered kin through marriage also varies by culture and time period.
    – bgwiehle
    Commented Dec 1, 2013 at 20:45
  • 1
    This is almost right, except for the first five words :-).
    – cleaverkin
    Commented Dec 3, 2013 at 22:24

Not the answer you're looking for? Browse other questions tagged or ask your own question.