Romans 1:24-27 uses "natural function" (physiken chresin) as the key term defining appropriate sexual expression; lesbian and male homosexual acts are condemned as exchanges of the natural for the unnatural.

Mike reads Romans 1:24-27 carefully, noting the repeated "natural/unnatural" language. He argues that what counts as sinful is what exchanges the natural sexual function for something unnatural. This framework then applies beyond homosexuality to evaluate any sexual act.