I think a more proper name for it would be Same Gender Union. We are different genders, not different sexes. Sex is something we do, not something we are.
I would disagree. Sex is what we are. Gender has only to do with grammar and nothing to do with human sex or sexuality
Sex is the property or quality by which organisms are classified as female or male on the basis of their reproductive organs and functions.
Gender on the other hand is a grammatical category used in the classification of nouns, pronouns, adjectives, and, in some languages, verbs that may be based on characteristics such as sex that determines agreement with or selection of modifiers, referents, or grammatical forms.
The word sex is often used to describe intercourse as in; "we had sex" while "we had gender" is virtually never used. I believe the incorrect use of the word "gender" came into vogue when political correctness implied that the word "sex" could be offensive to some.