Is there a moral obligation to treat everyone equally? Is it ever moral to give preferential treatment to others?

Ethical Position Paper
Equal Treatment of Others
Is there a moral obligation to treat everyone equally? Is it ever moral to give preferential treatment to others? If so, when is it acceptable and when is it not acceptable?
This paper will address the idea of equal treatment and when people have a moral obligation to treat people without preference.
Define equal treatment. Address the following types of relationships and whether it is moral or immoral to give preferential treatment to someone because of the relationship. • Immediate Family (Parent to child or siblings) • Extended Family (Grandparent to child or close cousins) • Further Extended Family (Related by marriage or more distant cousins) • Tribal/Ethnic/Racial Affiliation (Shares a common ancestor or common ethnic heritage or race) • Religious Affiliation (Shares a common faith) • Geographic/Regional Affiliation (Shares a common regional or geographic identity) • Same Sex (Men giving preference to men or women giving preference to women) • Marital Status (Giving preference based on being married or not) • Sexuality (Giving preference based on similar sexual expression) • Socioeconomic status (Giving preference based on education, wealth, or occupation)
Is it ever moral to give preference to someone based on each of these relationships? Why? Is it ever immoral to give preference to someone based on each of these relationships? Why?
Provide arguments for your positions focusing on what makes the difference between one action being moral and another being immoral.