Theory:

Family Relationships in English & Names of Family Members
  
Family or Blood Relationship means persons connected by relations like – father-mother, son-daughter, brother-sister, grandfather-grandmother, uncle-aunt, nephew-niece, brother-in-law, sister-in-law, etc. 
 
NumbersMale FemaleRelationship
1.FatherMotherParent
2.Son DaughterChild
3.HusbandWifeSpouse
4.BrotherSisterSibling
5.GrandfatherGrandmotherGrandparents
6.GrandsonGranddaughterGrandchild
7.UncleAuntParent's siblings
8.NephewNieceSibling's child