Conversion therapy refers to a range of unscientific, discredited and harmful heterosexist practices that attempt to re-align an individual’s sexual orientation, usually from non-heterosexual to heterosexual. In Australia, the state of Victoria recently joined Queensland and the Australian Capital Territory in criminalising conversion therapy. Although many other jurisdictions have also introduced legislation banning conversion therapy, it persists in over 60 countries. Children are particularly vulnerable to the harmful effects of conversion therapy, which can include coercion, rejection, isolation and blame. However, if new biotechnologies create safe and effective conversion therapies, the question posed here is whether it would ever be morally permissible to use them. In addressing this question, we need to closely examine the individual’s circumstances and the prevailing social context in which conversion therapy is employed. I argue that, even in a sexually unjust world, conversion therapy may be morally permissible if it were the only safe and effective means of relieving intense anguish and dysphoria for the individual. The person providing the conversion therapy must be qualified, sufficiently independent from any religious organisation and must provide conversion therapy in a way that is positively affirming of the individual and their existing sexuality.