Sexuality encompasses various dimensions within a society, such as beliefs, human acts, individual identities etc. It is a subjective matter which does not have a concrete and specific definition, instead, it is constructed based on human beliefs throughout thousands of years of human development, and also personal perspective. Sexuality gradually arose in order to satisfy individuals’ basic biological needs, which is fundamental in human development. It is an essential component in every society to maintain its order (i.e. to balance sexual needs and respect among people), without which the society would become disordered.

What is ‘normal’ human sexuality? Human sexuality would be considered as ‘normal’ when the idea is generally accepted. It is based on social perceptions, ethical and religious beliefs. For instance, from the Youth Sexuality Study 2011 by the Family Planning Association of Hong Kong, over 95% interviewees regard themselves as heterosexual (while 3% said they don’t know). In such case heterosexual would be regarded as normal. Another reason is that religious dogma usually have certain restrictions on sexuality. For example, in the Christian’s perspective, the god and the bible are clearly against homosexuality. In some countries like Vatican City, Italy and Mexico, the church is a symbol of power where its follower should obey its rules. In such conditions heterosexuality is praised while homosexuality is considered as abnormal.

In recent years, people