This article, the first of two, looks at the issue of sexuality in health care. Sexuality underpins much of what a person is and has significance in everyone's life. Through sexuality, people express their most intimate feelings of individuality and their need for emotional closeness with other human beings. Sexuality is not just about sexual intercourse, it is about the concept of people as men and women — about their manliness or femininity. Sexuality also affects the way people see themselves or would like to be seen, their appearance and behaviour, and their desire to attract those who matter to them. It is about the fears and fantasies people have about themselves and others. Nurses need to have an understanding of sexuality as they may have a crucial part to play in its dynamic progress.