Final answer:
The term that correctly describes someone whose gender identity does not match their sex assigned at birth is 'transgender.' 'Transgender' is not synonymous with gender dysphoria, which refers to the psychological distress from a gender identity and sex assignment mismatch.
Step-by-step explanation:
The term that best describes a category whereby one's sexual identity as either a man or a woman does not match the sex that they were assigned to at birth is transgender. Transgender people have a gender identity that differs from the sex they were assigned at birth. Meanwhile, gender dysphoria is a term used to describe the distress a person feels due to a mismatch between their gender identity and their sex assigned at birth. However, not all transgender people experience gender dysphoria. Cisgender individuals identify with the sex they were assigned at birth, and intersex refers to individuals with physical sex characteristics that do not fit typical binary notions of male or female bodies.