Some aspects of the mestizoized urban culture in Mexico are linked to male homosexuality in support of the theory that cultural factors play an important role in the kind of life styles and sex practices of males involved in homosexual behavior. The following factors are considered relevant: the sharp dichotomization of gender roles, dual categorization of females as good or bad, separate social networks maintained by males before and after marriage, proportion of unmarried males, and distribution of income. One result of the sharp dichotomization of male and female gender roles is the widely held belief that effeminate males generally prefer to play the female role rather than the male. Effeminacy and homosexuality are also linked by the belief that as a result of this role preference effeminate males are sexually interested only in masculine males with whom they play the passive sex role. The participation of masculine males in homosexual encounters is related in part to a relatively high level of sexual awareness in combination with the lack of stigmatization of the insertor sex role and in part to the restraints placed on alternative sexual outlets by available income and/or marital status. Males involved in homosexual behavior in Mexico operate in a sociocultural environment which gives rise to expectations that they should play either the insertee or insertor sex role but not both and that they should obtain ultimate sexual satisfaction with anal intercourse rather than fellatio. In spite of cultural imperatives, however, individual preferences stemming from other variables such as personality needs, sexual gratification, desires of wanted partners, and amount of involvement may override the imperatives with resulting variations in sexual behavior patterns.