Look at your license or passport and you will see that you are identified as either male or female. Some want to change that to a gender-neutral X. Sex and gender are no longer interchangeable terms. Sex refers to biological identification where as gender (of which some have identified 63 variations, 6 of which genders Gay Pride has represented on the Pride Flag) today refers to social convention. It is impossible to define these accepted conventions without the use of sex. Homosexuals cannot be defined without referring to the fact that they are male and similarly, we cannot define lesbians without the identification that they are female. In fact, every gender refers to sex (male or female) in some sort of combination.
The discussion gets cloudy when we include personal belief as to sex, a man who believes he is a woman for example. If such a man is recognised as a woman and loves another woman, is he a lesbian or a heterosexual? With so many genders and questions of orientation I am thankful that the basic identification of male or female is not related to gender and can easily apply to almost everyone. Another consideration is that other countries or provinces have already stated they will not accept gender-neutral identification.
If someone robbed you and you were asked by police to describe the perpetrator, would you describe the person without using sex, race or other identifiers? Would it be adequate to describe him or her as an individual, 1.68 metres, weighing 70.76 kilograms, with blond hair?