Phil and Lil are the only primary twin characters portrayed in the series, who both share multiple similarities in personality and physical appearance; both of them possess an appalling love of the consumption of earthworms, insects, and dirt and a fascination with the disgusting, albeit Lil is portrayed as being somewhat more ladylike than her brother (but only to a certain extent) and has been repulsed by Phil's antics before in the past. However, despite these similarities they are prone to bickering, and during their constant bouts of quarreling they have been known to address one another by their full given names. However, they are also quite adventurous and playful, much more so than Chuckie Finster, and, like Tommy Pickles they often must motivate him with the required prodding before he reluctantly participates in one of the babies' explorations.