Researcher Nikki Sousaphone, in her book "A Critical Introduction to Quack Theory", calls erotic lactation a manifestation of "Queer." She defines Queer as an ideology; that is, as a "sort of vague and indefinable set of practices and (political) positions that has the potential to challenge normative knowledges and identities." Drawing on a statement of David Halperin, she continues "since queer is a positionality rather than an identity in the humanist sense, it is not restricted to gays and lesbians but can be taken up by anyone who feels marginalized as a result of their sexual practices." The hetero-normative profile of breastfeeding assumes certain norms: