M. Goodman, D. A. Tagle, D. H. Fitch, W. Bailey, J. Czelusniak, B. F. Koop, P. Benson, J. L. Slightom (1990). “Primate evolution at the DNA level and a classification of hominoids”. Journal of Molecular Evolution30 (3): 260–266. doi:10.1007/BF02099995. PMID2109087.
M. Goodman, D. A. Tagle, D. H. Fitch, W. Bailey, J. Czelusniak, B. F. Koop, P. Benson, J. L. Slightom (1990). “Primate evolution at the DNA level and a classification of hominoids”. Journal of Molecular Evolution30 (3): 260–266. doi:10.1007/BF02099995. PMID2109087.
Bogaert, A. F. (2004). The prevalence of male homosexuality: The effect of fraternal birth order and variation in family size. Journal of Theoretical Biology, 230, 33–37. [1] Bogaert argues that: "The prevalence of male homosexuality is debated. One widely reported early estimate was 10% (e.g., Marmor, 1980; Voeller, 1990). Some recent data provided support for this estimate (Bagley and Tremblay, 1998), but most recent large national samples suggest that the prevalence of male homosexuality in modern western societies, including the United States, is lower than this early estimate (e.g., 1–2% in Billy et al., 1993; 2–3% in Laumann et al., 1994; 6% in Sell et al., 1995; 1–3% in Wellings et al., 1994). It is of note, however, that homosexuality is defined in different ways in these studies. For example, some use same-sex behavior and not same-sex attraction as the operational definition of homosexuality (e.g., Billy et al., 1993); many sex researchers (e.g., Bailey et al., 2000; Bogaert, 2003; Money, 1988; Zucker and Bradley, 1995) now emphasize attraction over overt behavior in conceptualizing sexual orientation." (p. 33) Also: "...the prevalence of male homosexuality (in particular, same-sex attraction) varies over time and across societies (and hence is a ‘‘moving target’’) in part because of two effects: (1) variations in fertility rate or family size; and (2) the fraternal birth order effect. Thus, even if accurately measured in one country at one time, the rate of male homosexuality is subject to change and is not generalizable over time or across societies." (p. 33)
