Even using the word "gender" here is preemptively handing the victory to the perverts.
The word is "sex." Biological "sex." That would be male or female. We are a species that exhibits "sexual" differentiation.
"Gender," on the other hand, is primarily a grammatical term, and has no necessary connection with the two sexes. In languages which have gendered nouns, there's no sexual reason why el brazo (the arm) is masculine, but la piedra (the leg) is feminine.
"Gender" is fluid, subjective, and even whimsical. "Sex" is objective.
Say "sex."