Susan is a super genius scientist. She is the younger twin of her sister Mary. Susan has been shown to be less empathetic and sympathetic than her sister. Susan is prone to believing in the more scientific and logical explanations for things rather than the illogical and magical explanations. Her sister is more open-minded, and Mary is frequently proven correct. Susan seems to be less level-headed than her twin Mary, and tends to be less conservative, as she speaks her mind much more frequently. Susan has completely straight red hair and wears square glasses. Without her glasses she has very poor vision and her eyes show strain.

 

Mary is a super genius and the older twin sister of Susan and also the older sister of Johnny. Mary has been shown to be more empathetic and sympathetic than her sister. Mary is prone to believing in the less scientific and more science-fictional, which, although it receives scorn from her twin, often proves to be correct in the end. Mary seems to be more level-headed than her twin Susan, and Mary tends to be more conservative, as she speaks her mind much less than Susan. Though Mary wears pants, she seems to be more "girly" than her twin Susan. Mary has a light yellow t-shirt with a blue moon on it, long curly red hair, and a moon-shaped barrette