Sexual behaviour is a diverse phenomenon and occurs in several physical situations, social contexts and is experienced differently by everyone. Everyone has a complex set of motivations and external influences that determine the decision to engage in sexual behaviour. It is difficult to answer all the questions about sexuality within one discipline. The study of sexuality is important for the following reasons:The exchange of sexual information is a taboo in many societies.For many people, sexuality is an important motivation in life.Some people experience difficulties and problems with their sexual functioning. The definition of gender is whether someone is male, female or other, such as trans. However, sometimes the word sex is used to describe gender, for example on a job application form. Most of the times sex refers to sexual behaviour or reproduction. The ambiguity in the use of the word sex causes confusion. In the context of this book, the term sex describes sexual activity and gender refers to being male, female or other. Besides the ambiguity in the use of the word sex, there are other problems with the difference between sex and gender. A lot of contemporary research is based on the gender...