“…In laboratory studies, self-identified heterosexual women, on average, have been shown to have a generalized genital response to both sexes, while heterosexual men have been shown to have a modest genital response to male sexual stimuli (e.g., Chivers, Rieger, Latty, & Bailey, 2004;Chivers, Seto, Lalumiere, Laan, & Grimbos, 2010;Rieger, Chivers, & Bailey, 2005). This has led a number of investigators to propose that same-sex sexual behavior may have some direct adaptive value (Kirkpatrick, 2000;Muscarella, Cevallos, Siler-Knogl, & Peterson, 2005).…”