Seriously. They provide oodles of material for her horror books, and they support the creepiness inherent in her work. She constantly threatens me with, "one of these days, we are packing up and moving to Kyoto!"
More information about Yotaro can be found here. Roughly translated:
" YOTARO (Yotarou). Robot baby with a soft body temperature. Have a soft cheek, in body temperature, or sneezing, or runny nose, and I'll grin and cradles and legs Jitabata or reproduction program the robot hand movement and emotion and such a baby is that this is YOTARO."