Sex refers to one's classification as male or female based on certain anatomical characteristics and the experiencing of erotic pleasure and the set of behaviors to create them. Sexuality consists of the aspects of a person's sense of self that are used to create sexual experiences. Personality and social characteristics that are expected of members of one sex and not the other, and which set by culture and not biology, are referred to as Choose...orientation dimensiongametic differentiationgender rolessex differences. Sexual orientation is the tendency to be attracted to, and be desirous of, intimate relations with a partner of a particular sex, either one's own sex (homosexual) or the other sex (heterosexual). Much of a person's sexual biology is designed to support reproduction. Males manufacture sperm and females manufacture eggs, and the anatomies of each sex are specialized to bring sperm and egg together at fertilization, which most often takes place in the Choose...uterusfallopian tubesovariesvas deferens. Eggs are produced approximately monthly near the middle of a woman's Choose...menstrual cyclemenarchemenopauseendometrium. Sperm are produced continually by the Choose...epididymistestesCowper's glandsseminal vesicles. Upon ejaculation, the sperm become mixed with seminal fluid to become semen. Sexual arousal and response can be described by the four-phase Sexual Response Cycle. When a person psychologically and socially permits him or herself to become turned on sexually, blood flows to the pelvic region and skeletal muscles become tense. With sufficient sexual stimulation, psychological and physical tensions built up during sexual activity can be released in orgasm. Some individuals can experience difficulties with sexual arousal and response, including lacking interest in sex, problems with becoming sexually aroused or orgasm, and experiencing pain during intercourse. Positive sexual relationships most often develop out of emotionally close, intimate relationships. These kinds of relationships are built on mutual trust and responsiveness, which develops over time between two people by the mutual exchange of private information about the self, called Choose...similarityproximityself-disclosureself-enhancement. Intimate relationships are maintained by healthy, interpersonal communication, which is both symbolic (eg: the giving of gifts) and spoken. Positive spoken communication involves sending clear messages with the use of Choose...You-statementsI-statementsempathymetamessages, which represent the speaker's thoughts and intentions. Effective communication also involves Choose...listening; feedbackYou-statements; I-statementsliteral messages and metamessagesempathy and You-statements, which fosters clarity and trust.