Most definitions of sexual orientation include a psychological component, such as the direction of an individual's erotic desires, or a behavioral component, which focuses on the sex of the individual's sexual partner/s. Some people prefer simply to follow an individual's self-definition or identity. Scientific and professional understanding is that "the core attractions that form the basis for adult sexual orientation typically emerge between middle childhood and early adolescence". Sexual orientation differs from sexual identity in that it encompasses relationships with others, while sexual identity is a concept of self.