Discussion
adolescence
Girl2Girl is the first comprehensive mHealth teenage pregnancy prevention intervention developed and tested nationally, as well as one of the first pregnancy prevention programs developed for cisgender sexual minority girls of which we are aware. As previously reported (Ybarra et al., The intervention development was guided by the Information-Motivation-Behavioral Skills model of (HIV) prevention (Fisher & Fisher, The lack of intervention impact for younger girls could be due to neurocognitive development. Self-control in adolescence is diminished because subcortical limbic systems have greater influence than cortical systems during this time relative to adulthood (Casey, Differential power in the sexual relationship may be another reason why we see different intervention impacts by age. Miller and colleagues found that younger girls were more likely than older girls to have a larger gap between their age and that of their sexual partner, and they were more likely to report having been coerced or forced to have sex (Miller et al., The effect that Girl2Girl had on pregnancy preventive behaviors for lesbian girls is less clear than its effect for bisexual girls. One in four lesbian girls had penile-vaginal sex during the observation period compared to one in two bisexual girls. As such, statistical power may be an issue. Perhaps with a larger sample, significant intervention effects might have been detected for lesbian girls. Importantly, retention rates were similar for lesbian and bisexual girls This suggests that there was not differential drop out because lesbian girls found the content to be less relevant than bisexual girls did, although it is possible that lesbian girls paid less attention to the content over time. Focus groups conducted during the formative phase suggested that some lesbian girls did not anticipate the possibility of, nor desire, penile-vaginal sex (Ybarra et al., 