### Instruction: How do the definitions of "first-degree relative" and "nuclear family" differ?
### Input: A first-degree relative (FDR) is a person's parent (father or mother), full sibling (brother or sister) or child. It constitutes a category of family members that largely overlaps with the term nuclear family, but without spouses.
### Response: Nuclear family includes spouses while first-degree relatives are only blood related.