A social construct is associated with the concept of Social Constructionism and is a supposedly unnatural relationship, moral or ethical ideal, or other idea about human life. Charges of having created a social construct are typically advanced by advocates of gay rights or feminism. It is more broadly part of the political correctness movement. An example of its usage would be: "gender differences are just a social construct." This is a way of denying the real differences between men and women.
The main premise is that humans construct their social reality, rather than having it imposed upon them. As a result of the nature of social constructs, their definition is constantly in flux as norms and values of society constantly change. For instance, as attitudes toward homosexuality, premarital sex, and other cultural phenomena change, their definition changes. In some cases, activities once considered perfectly normal become deviant, and deviant behaviours become perfectly normal. A comprehensive example of the shift in definitions comes from the narcotics legislation introduced in Canada in the 1920s. Prior to 1923, marijuana was an uncontrolled substance. However, as a crackdown on opium dens began in British Columbia, and a moral panic began regarding drugs, there was a sudden change in the status of marijuana. Marijuana itself was not the subject of any debate, nor was it included in the initial readings of the introduced legislation. More than likely, it was written in at the last minute, with no member of parliament having significant feelings one way or another, nor was it supported by any significant scientific evidence regarding its harmful nature. To this day the behaviour of marijuana use is formally considered deviant, and therefore a crime. The definition of the behaviour is socially constructed, as there is no natural reason for it to be a crime.
Two examples of behavior that was once considered normal but would now be considered deviant by most Americans is that related to slavery and the cruel and unusual punishment of criminals.