In biology, a pair bond is the strong affinity that develops in some species between a mating pair, often leading to the production and rearing of offspring and potentially a lifelong bond. Pair-bonding is a term coined in the 1940s that is frequently used in sociobiology and evolutionary biology circles. The term often implies either a lifelong socially monogamous relationship or a stage of mating interaction in socially monogamous species. It is sometimes used in reference to human relationships.