I am treated differently than my co-workers, who are five men and one woman. My boss treats the other woman in our group different than me but the same as the man. Does this mean that I cannot successfully claim sex discrimination?

Not necessarily, because courts have ruled that a "sex discrimination claim does not fail simply because an employer does not discriminate against every member of the plaintiff's sex." Pitre v W. Elec. Co., 843 F2d 1262 (10th Cir. 1988). Both federal law (Title VII of the 1964 Civil Rights Act) and Kentucky state law prohibit sex discrimination in employment.