Sex is important and should be studied.
Since most humans desire to have sex and/or relationships, discussing sex-related topics within the context of individual happiness is vital.
Sex can be the root of dysfunction, trauma, anxiety,good health, pleasure, relationship dynamics, unwanted pregnancy, contracting disease/illness, stress reducing, among other conflicting "good" and "bad" consequences.
Historically, sex has shaped civil rights movements, conflicts, cultural wars, economics, health policy, among other institutions at a local and global level. Moreover, sex is motivates the inherent human desire to furthering one's social superiority whether it is physical appearance or appearance of weath (why we may choose to buy that sportscar).