This short discussion here cannot take on the whole question of sexual orientation, but what I can do is review briefly some of the contribution that data on the social construction of sexuality add to this complex debate. Let me state what I believe are the main arguments that support the importance of a sociological stance on this topic.
First, we should remember that sexual identity is often more than sexual fantasy, desire, or behavior. Many people who consider themselves heterosexual have some capacity, however minor, for homosexuality. This does not mean they are truly homosexual any more than a capacity for heterosexuality means a homosexual is able to take on a heterosexual identity or relationship. Studies show that some individuals are able to eroticize both sexes while maintaining strong feelings for only one. Conversely, individuals may never have a same-sex sexual contact and know, in their deepest sense of self, that that is what compels their deepest passions. Yet again, there are those who maintain equally strong affections and attractions to both sexes fluctuating across the life cycle--changing identities as circumstances change. Completely bisexual people are rare, yet their very existence requires at least as much of a social explanation as a biological one (P. Blumstein, P. Schwartz, Journal of Social Issues, 33:30- 45, 1977). The point is that sexual orientation is complex -- not only to the researcher but also to the participant.
Second, we should assume from the voluminous literature on social interaction that human contact, cognition, and personality are important parts of individual attachment and desire. Even if we are biologically influenced in favor of either heterosexuality or homosexuality, the happenstance of social events and individual interpretation of these events can alter a sexual program. Pat two kids on the head: One will feel rewarded, the other will feel warned.