Nobody should be discriminated against based on involuntary factors such as race, gender, national origin, etc., unless there is a compelling reason to do so. However, all other ‘chosen’ characteristics should be amenable to discrimination for various purposes.
Religion could be a valid factor to consider in the discrimination of people because it is a chosen characteristic. However, race, sex, national origin, etc., should not be discriminated against.
Sexual Orientation Discrimination
Unlike race, ethnicity, nationality and gender, sexual orientation may be a factor eligible for discrimination in some areas such as employment in the private sector because there may be a significant element of choice involved. Though sexual orientation is likely heavily influenced by genetics, it may still be considered, to some extent, as a notable defect equivalent to alcoholism, problem gambling, general criminal behavior, Attention Deficit/Hyperactivity Disorders (ADD/ADHD), Obsessive Compulsive Disorders (OCD) and other character traits which have also been shown to have significant (though perhaps not as significant as homosexuality) genetic influences. Homosexuality may be considered a genetic defect, and any available treatments and counseling should be made available, as would be the case for the attempted removal of any other undesirable characteristic, genetically influenced or not.
These traits, in which choice is a significant factor, should be allowed to be used for only certain discriminatory purposes, such as hiring for employment by a private employer, choosing a tenant for occupation of rental properties, and other long-term, close contact or otherwise relatively close relationships. All private organizations ought to have the right to discriminate, using these allowable traits, in the hiring, firing, membership, and attendance within their organizations. Refusing to provide any goods or services to homosexuals should be banned. Public sector organizations should be prohibited from using homosexuality as a characteristic for discrimination.
Nobody should be discriminated against solely on the basis of age. For example, mandatory retirement for firefighters or police officers, etc., over a certain age should be prohibited. Other factors that are age-related could be used as disqualifying criteria, such as loss of physical strength, endurance, etc., but discriminating against age alone should be unjustified.
Seniority and Job Security
Seniority should not be a factor for anything in government neither should it mean anything meaningful in the private sector. Seniority should especially not be a factor in determining job security or pay raises.
Neither place of birth (native or foreign born) nor age should be deciding or influencing factors determining whether or not a person is qualified to hold any elected public office, including the US Presidency.