Suggestively…
I was taught in my undergraduate sociolinguistics class that sex is an essentially binary biological definition, while gender is a gradient social construct. However, gender is often substituted for sex in order avoid any implication of the alternate, somewhat taboo interpretation of the latter. Such was the case on a form that participants were required to fill out for a study my friend E has been conducting. One participant grumbled that he did not like the use of gender to mean sex, as it made him think of grammatical gender.
Asked E ‘Would you rather have sex then?’.
[E and the participant, another friend, independently reported this incident to me with some glee.]