Powlison's perspective both broadens and nuances the discussion. For example, he discusses biological predisposition to homosexuality in the context of biological predispositions that we all have. He also digs a bit deeper into the motivational patterns for lesbianism.
He also speculates as to what sort of genetic ratio we might see if an "H-gene" is every discovered behind homosexuality (though the ratio, he says in personal correspondence, is probably stronger than anything that will be discovered). But genetic findings won't be determinative--they will only slide a bell curve one direction or the other.
Powlison often talks about his three children, and that within 10 minutes of their birth he and his wife could see instinctive qualities that showed a continuity with what would prove to be their characteristic gifts and typical tendencies.
The point is that our various "tendencies" are part of a complex picture of the way in which all of us--not just homosexuals--work.
Here's the relevant section from Powlison's essay:
[Myers's] case study of homosexuality . . . illustrated how a scientist’s interpretive grid can introduce biases, propelling him to do hard thinking with frail data in order to contradict the mind of Christ. The facts that “prove” the legitimacy of homosexual orientation – chiefly the experience of ongoing struggle and cases of recidivism among those who attempt to change – equally “prove” the legitimacy of the historic Christian view that homosexuality is a typical sin from which God progressively redeems his children.It is no surprise that people being redeemed out of homosexual lust still battle with temptations – and that some fall back. This is true of every pattern of sexual lust, not only homosexuality: a woman whose romantic-erotic fantasies are energized by reading romance novels and watching Tom Cruise in Top Gun; a man whose eyes rove for a voyeuristic glimpse down a blouse; a woman aroused by sadomasochistic activities and implements; a man obsessed with young girls. In each of these cases, lust has been patterned around a characteristic object; love will learn a different pattern in Christ’s lifelong school for reorienting the disoriented.
But there is no reason that an energetic, ideologically committed researcher could not find some data that might suggest that each of these sexual disorientations might arise from some biological predisposition. What if future research suggests that a particular personality characteristic, brain structure, hormone level, and perceptual style correlates to adult-to-child homosexuality? To bestiality? To heterosexual promiscuity? The last mentioned might even prove the strong case for the style of argument Myers makes. Would his argument generalize to these cases? He would have to say Yes, if the statistics seemed to tilt that way. If any of the above persons continue to struggle, or at some point slid back into old patterns, then it might mean that their particular morph of sexuality is innate and valid.I’m not familiar with the studies of female homosexuality, but let me offer an “unscientific” observation arising from pastoral experience. I’ve known many lesbians driven more by “intimacy lusts” than by the unvarnished eroticism of many heterosexual or homosexual males. In fact, most of them had once been actively heterosexual, unsuccessfully looking for love from a man or men. They eventually found that other women were similarly wired to intimacy and companionship as the context for erotic feelings. An emotional closeness initially developed that was progressively sexualized during the process of redefining oneself as a lesbian. Such a process makes lucid sense on the Faith’s analysis of the outworking and inworking of sin. And I’ve seen the fiercely tender grace of God break in, progressively rewiring some of these women. Statistics might give definition to words such as “most,” “many,” and “some.” But statistics could neither confirm nor disconfirm the point of view whose plausibility is established theologically, anecdotally, and pastorally.
Myers’s biological data on homosexuality was admittedly rather dim light, not something that could drag a researcher along who was not otherwise willing. But let me offer another “unscientific” comment about data that might yet be discovered. When or if the “homosexuality gene” is discovered, I predict that the facts will be of the following kind. Among people without the H-gene, say 1.5% are oriented towards homosexuality, while among people with the H-gene, say 15% are oriented towards homosexuality. That would be a very significant statistical difference. But what would it prove? Only that characteristic temptations differ, that our bodies are one locus of temptation, that nothing is deterministic either way. It will be analogous to finding any other “gene for sin.” Those with the “worry gene,” the “anger gene,” the “addictive pleasure gene,” or the “kleptomania gene” will be prone to the respective sins. Such findings cause no problem for the Faith. They do trouble a Pelagian view that defines sin only as conscious “choice.” But sin is an unsearchable morass of disposition, drift, willful choice, unwitting impulse, obsession, compulsion, seeming happenstance, the devil’s appetite for souls, the world’s shaping influence, and God’s hardening of hard hearts. Of course biological factors are at work: we are embodied sinners and saints. That some people may be more prone to homosexuality is no more significant that that some may be more prone to worry.Grace is similarly personalized. Some of God’s children find Phillipians 4:4-9 breathes particular comfort amid their besetting temptation to anxiety. Others find the Spirit pacifying their fierce temper and writing James 3:1-4:12 on their hearts. Still others find Proverbs 23:29-35 clobbers them about the madness of their heavy drinking, and that they grow wiser as they quit hanging out with old drinking buddies and spend time with new, wiser companions (Prov. 13:20). Still others experience a keen-edged joy in earning a pay check, paying for things they once stole, and sharing money with people in need (Eph 4:28). Others find that Christ’s comprehensive vision for rearranging everyone’s sexuality – in the whole Bible, not just “a half dozen verses” – reaches into their particular form of disorientation, teaching them to love people, not lust after them. One and all, former neurotics, rageaholics, drunks, thieves, and gays find that truth rings true and rings with hope.
Each of us deals with what Richard Lovelace termed “characteristic flesh” (Lovelace, Dynamics of Spiritual Life, p. 110). Repeat temptations and instances of recidivism do not change the rules. Strugglers with indwelling sin genuinely grow in grace, but often the generic issue remains on stage in some manner throughout a person’s lifetime. Abiding struggles are no reason to throw over the Christian life which is defined as growth amid struggle unto a future perfection (1 John 3:1-3). Those being redeemed out of homosexualized lust are examples of the rule, not exceptions granted license to give up the fight and rationalize their sin.