Suppose you are explaining the participants section of a research article to a first-year student. you explain that researchers use when referring to male-female differences that are learned and to designate biological differences.

Gender - Sex.

Explanation:

The distinction between gender and sex differentiates a person's biological sex (the anatomy of the individual) from the gender, which is related to how one sees him/herself, with the personal identification of one's own gender.

As the exercise details, gender is used when referring to male-female-other differences that are learned and sex to designate biological, anatomical differences of one's sexual reproduction system.