Background: Tuberous sclerosis complex (TSC) is a genetic disorder associated with a range of neurocognitive manifestations, including neuropsychological attention deficits most notably in dual tasking/divided attention. These dual-task deficits have so far been interpreted as evidence of a vulnerable "cognitive module" in TSC. Here, we suggest that this interpretation represents an "adult neuropsychological" perspective, and argue that a developmental approach would be more appropriate to examine attention deficits in TSC. Method: We examined the pathway to "endstate" dual-task deficits in twenty 6-16 year olds with TSC utilising the Test of Everyday Attention for Children (TEA-Ch). We predicted that the pattern of attentional deficits in TSC would support a "conditional" model where the establishment of a later-maturing skill was dependent on the functional maturation of an earlier expected skill. Results: Attentional profiles showed statistical support for a conditional model. Only one child showed a deterministic pattern while one showed a hybrid pattern, attributed to the admixture of a surgically acquired lesion and a neurodevelopmental disorder. Conclusion: This preliminary study suggests that the developmental cascade in TSC may be arrested at various stages of neuropsychological development, thus leading to different developmental trajectories towards similar "endstate" profiles.