Published online by Cambridge University Press: 14 January 2010
In most cultures, marriage vows entail the promise of fidelity and lifelong commitment. In principle, marriage vows are a contract – a reproductive contract – between two individuals to maintain both emotional and sexual fidelity to one another ‘til death do them part.’ Monogamy. There are few species that maintain monogamous relationships between the sexes. It is commonly believed that males are more promiscuous, but new research is shedding light on the prominence of female infidelity as well as the consequences of such behavior.
Female infidelity is common in the animal kingdom as well as among humans. According to an analysis of 280 000 paternity tests conducted in 1999 by the American Association of Blood Banks, approximately 30% of children are fathered by extra-pair copulations; that is, 30% of children in this sample were fathered by someone other than the woman's long-term romantic partner. Several case studies exemplify this phenomenon and the associated psychological and social consequences. The New York Times reported a case of a Texas man who was faced with the unnerving news that not one, but several, of his children were the product of extra-pair paternity. The bittersweet news came when the man was being tested as a carrier for a debilitating genetic disorder that his youngest daughter had suffered with since birth. When the genetic test came back negative he should have been elated, but knowing that both parents must be carriers for any child to be inflicted with the disorder raised obvious concerns.