This paper explores individual differences in children's (8 to 14 months) developmental trajectories of lexical comprehension and production, with a specific focus on gender differences, using two analytic approaches, involving traditional parametric statistics and classification procedures. Both techniques show that girls' lexical development outpaces that of boys. The inductive approach also reveals the existence of distinct “fast” and “slow” comprehension and production trajectories, that are not exclusively determined by gender.