What is the "male pair-bonding" gene?

The "male pair-bonding" gene is sometimes referred to as the "male infidelity" gene. It is a genetic variant of the AVPR1A gene. The AVPR1A gene encodes a protein called arginine vasopressin receptor 1A. AVPR1A variation can occur in the regulatory region of the gene at three different repetitive sequences, known as RS1, RS3 and GT25. A specific version of RS3, known as the RS3 334 allele is associated with diminished pair-boding in males.

Men with the RS3 334 allele are less likely to form a strong bond with their partners and are more likely to experience marital crisis or divorce. They are less likely to get married and more likely to cohabitate, than individuals without the RS3 334 allele. Spouses of men with the RS3 334 allele report feeling less affection and consensus in the marriage. These associations are not seen in women with the RS3 334 allele. However, an increased likelihood of infidelity in females is associated with five different changes in the AVPR1A gene.