Linked from
The 25 pages that link to Human sexual activity, each with the reason it gives.
AsexualityRelated: Behavior alone does not establish whether someone is asexual.
Sexual fantasyRelated: Fantasy is mental content; behavior is what a person actually does.
HeterosexualityRelated: Behavior alone does not establish whether someone is heterosexual.
ZoophiliaRelated: Attraction does not establish whether a person has engaged in sexual behavior.