An official State of Texas website.
Revision 21-1; Effective June 23, 2021
A person is considered to be a relative if the person is related within the fourth degree of consanguinity or within the second degree of affinity.
Relationships of Consanguinity
Two people are related to each other by consanguinity if one is a descendant of the other or if they share a common ancestor. An adopted child is considered to be a child of the adoptive parent for this purpose.
Degrees of Consanguinity
| Individual | 1st Degree | 2nd Degree | 3rd Degree | 4th Degree |
|---|---|---|---|---|
| Person | child parent | grandchild, sister, brother, grandparent | great grandchild, niece, nephew, *aunt, *uncle, great grandparent | great-great grandchild, grandniece, grandnephew, first cousin, *great aunt, *great uncle, great-great grandparent |
*An aunt, uncle, great aunt or great uncle is related to a person by consanguinity only if he or she is the sibling of the person's parent or grandparent.
Example: Person A is related by the third degree of consanguinity to person B if person B is person A's uncle (brother of person A's father) because they share a common ancestor. However, person A is not related by consanguinity to person C if person C is the uncle's spouse because person A and person C share no common ancestor.
Relationships of Affinity
Two people are related by affinity if they are married to each other, or if one person’s spouse is related by consanguinity to the other person.
The ending of a marriage between two people by divorce or the death of a spouse ends relationships by affinity created by that marriage, unless a child of that marriage is living, in which case the marriage is considered to continue as long as a child of that marriage lives.
Degrees of Affinity
| Individual | 1st Degree | 2nd Degree |
|---|---|---|
| Person | spouse spouse’s child (stepchild) spouse’s parent child’s spouse parent’s spouse (stepparent) | spouse's grandchild (step grandchild) spouse's brother, spouse’s sister spouse's grandparent grandchild's spouse brother’s spouse, sister’s spouse grandparent’s spouse (step grandparent) |
Example: Person A is related by the second degree of affinity to the brother of person A's spouse because the brother and Person A’s spouse are related by the second degree of consanguinity.