belief and the methodology behind determining gender. Eugenides addresses how difficult it was for humans to devise a "universal classification for sex". Through Cal, scholar Angela Pattatucci Aragon stated, Eugenides opines that the 1876 system devised by Edwin Klebs that used gonad tissue to determine sex provides the most accurate answer. According to intersex activist and academic Morgan Holmes, Eugenides posits that a person's sexual attraction determines his or her gender. Cal's wish to become male because he desires females demonstrates a link between gender identity and sexuality. While Callie is not permitted to love the Obscure Object openly, Cal can freely love Julie. Holmes believed that the depiction of Callie "denies the legitimate place of lesbian desire and rewrites it as male heterosexuality." Book reviewer Georgia Warnke has a similar view. She wrote that by making these choices in the novel, Eugenides agrees with the belief that being attracted to females is "masculine" and thus it is "more natural" for a male to be attracted to a female than a female be attracted to a female. Daniel Mendelsohn of The New York Review of Books argued that Callie does not have to be a male in order to be drawn towards females; she could be gay. As an adult, Cal brags, "Breasts have the same effect on me as on anyone with my testosterone level." Mendelsohn noted that this assertion will astonish "Eugenides's (presumably testosterone-rich) gay male readership". Scholar Rachel Carroll agreed, writing that teenage Callie's erotic interest in girls is "retroactively explained and legitimized, by the discovery of his 'true biological nature'." Cal's gender identity postdates rather than predates his sexual interests. Carroll posited that Cal's inability to form heterosexual relationships as an adult is founded not upon his being intersex, but on his rejection of the sexual ambiguities that form his sexual interests as a youth. When Callie is in New York, she goes to the New York Public Library and searches for the meaning of the word "hermaphrodite"; she is shocked when the dictionary entry concludes with "See synonyms at MONSTER". Callie is not a Frankenstein; she is more like Bigfoot or the Loch Ness Monster. Bartkowski stated that Eugenides' message is "we must let our monsters out—they demand and deserve recognition—they are us: our same, self, others." Morgan Holmes, formerly of ISNA, describes how the book constructs an intersex character whose life reproduces "social fascination