Drosophila, like many creatures, indulge in gender-specific behaviours during courtship, behaviours that are often the result of sex-specific differences in the central nervous system. On p. 155, in a genetic screen for female behavioural mutants, Ditch and colleagues have identified retained/dead ringer (retn) as important for the development of the sexual behaviour of female flies. retn mutant females resist courtship and show fru-independent male-like behaviours(male-specific versions of fruitless (fru) determine many aspects of fly male courtship). Conversely, male retn mutants court normally. The researchers discover that mushroom body, photoreceptor and suboesophageal neurons form aberrant projections in retn mutant flies, indicating that retn affects the development of sex-specific neurons. The researchers propose that in female flies retn represses the development of the neuronal circuitry needed for male-like courtship; in male flies, fru expression overcomes this repression.