[exDemMom]

I do not like to use the word "sex" to refer to a person's gender, because it is too suggestive of a physical act. I can't speak for others, but I wouldn't be surprised if many of those who use "gender" to refer to a person's physical male or femaleness avoids using the word "sex" in that context for the same reason.

I checked a couple of on-line dictionaries. The use of the word "gender" to refer to physical traits is correct.

gender (noun)

2. either the male or female division of a species, especially as differentiated by social and cultural roles and behavior:
the feminine gender.

Compare sex (def 1).

Full Definition of GENDER

2 a: sex < the feminine gender >
b: the behavioral, cultural, or psychological traits typically associated with one sex

[HapaxLegamenon]

This is the dumbing down of the language. Until very recently gender was never used to refer to maleness or femaleness of a human being. My sex is male. The word male has a masculine gender.

Further evidence of the dumbing down is that you think the word sex is a verb. It is not. You do not sex. You have sexual intercourse.

Referring to new edition of a dictionary only proves my point.