noun

le sexe

sex

C’est la différence entre les hommes et les femmes, basée sur le corps et la reproduction.

Sexe is a masculine noun with several related meanings:

Sex: a biological classification, typically male or female, based on reproductive characteristics.
Gender or sex: a category used to distinguish people as male or female, depending on the context.
Sexual activity: sex or sexual intercourse, often in informal or general contexts.
Genitals: a person’s sexual organs, especially in a medical or literary context.

Le sexe is masculine; its plural is les sexes. It comes from Latin sexus, meaning “sex.”

genre — “gender”; often refers to social identity or roles rather than biological sex.
sexualité — “sexuality”; a broader term covering sexual feelings, identity and behavior.
organes génitaux — “genitals”; more explicit and precise than sexe when referring to body parts.

There is no general antonym for sexe.

sexe masculin — male sex
sexe féminin — female sex
faire l’amour — to have sex; a gentler expression than directly referring to sexual activity
avoir des rapports sexuels — to have sexual intercourse; a more formal expression