of homozygous due to the consanguinity under discussion. Thus, a parent and child pair has a value of r=0.5 (sharing 50% of DNA), siblings have a value of r=0.5, a parent's sibling has r=0.25 (25% of DNA), and first cousins have r=0.125 (12.5% of DNA). These are often expressed in terms of a percentage of shared DNA but can be also popularly referred to as % of genes although that terminology is technically incorrect.

As a working definition, unions contracted between persons biologically related as second