What is my brother-in-law's son to me?
Usually your nephew by marriage. If your brother-in-law is your sister's husband, his son with her is simply your nephew by blood. If he's your spouse's brother, his son is your spouse's nephew — your nephew by marriage, which everyday speech shortens to plain 'nephew' anyway. Only the paperwork distinguishes the two.
Relationship
Nephew by marriage
English has no single formal word for this relative — “nephew by marriage” is the label genealogists use.
- You
- Your brother-in-law
- His son
From the other side, you are their aunt or uncle by marriage.
This connection runs through a marriage, not a shared ancestor, so the ancestor chart can't draw it.
The calculator below works out blood relationships through a shared ancestor — use it to explore the rest of your tree.
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This relationship sits outside the shared-ancestor model, so the card above carries the answer and the calculator opens in its default state. Work out any blood relationship with it, or open the full relationship calculator.
FAQs
Is my brother-in-law's son my nephew?+
In everyday speech, yes. Genealogically it depends on whether the brother-in-law married your sibling (blood nephew) or is your spouse's sibling (nephew by marriage).
Who am I to my brother-in-law's son?+
Their aunt or uncle by marriage — or a blood aunt or uncle when the link runs through your own sibling.
Does the calculator store my family details?+
No — it runs entirely in your browser. Nothing you enter is uploaded or saved on our servers.
Start with one relative and see what comes back.
Add what you remember and AncestorIQ searches for the rest. Free to build your tree for as long as you like.
No credit card needed. Your tree stays yours.
