ginlazrirni lujvo

x1 is the biological/full/genetic-familial/'blood' parent of x2; x2 is the biological offspring/direct and immediate genetic-familial descendant of x1.

Step-parents are excluded, as are most other forms of parenting/rearing/raising/mentoring. Genetic clones may be included.

In notes:

x1 is a biological/genetic-familial/'blood' aunt/uncle of x2 by genetic-familial bond/tie/blood relation x3; x1 is a genetically and familially associated member of x2's genetic/biological parent(s)'s generation.