The “male pair-bonding” gene is a genetic variant of the AVPR1A gene. The AVPR1A gene encodes the arginine vasopressin receptor 1A, which binds vasopressin and transmits the signal into the cells.

Vasopressin is a hormone or “chemical messenger” that promotes water retention in the kidneys and increases blood pressure. Most of these effects take place when vasopressin is released into the blood stream.

Vasopressin can also be released directly into the brain and influence social and sexual behavior (such as infidelity). In people with the “male pair-bonding” version of the gene this signal transmission is disrupted.

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 people without the RS3 334 allele. Spouses of men with the RS3 334 allele report feeling less affection and consensus in the marriage.