There are three different AVPR1A variants (RS1, RS3 and GT25) that arise due to short tandem repeats (STRs) in the regulatory region, which controls AVPR1A protein levels.
A specific version of RS3, known as the RS3 334 allele, is associated with diminished pair-boding in males. The AVPR1A STR test determines the length of the RS3 repeat region, to find out whether a person has the RS3 334 infidelity variant.
