[From DMP]:
The Hybrid Child is an amazing android that can grow if it is lavished with enough love and care from its owner. Neither fully machine nor fully human, the various Hybrid Child models develop strong emotional bonds with their owners. This volume contains several short stories of love, sacrifice, and drama: Young Kotaro learns the importance of responsibility when his Hybrid Child's lifespan runs out. The tragic swordsman Seya learns to love again with the help of his Hybrid child, Yuzu. The final tale tells the story of Kuroda, the creator of the Hybrid Child designs, and how his lost love inspired their creation.

[From Mochi*Mochi]:

----I said that I wouldn't accept anything else but Hazuki--- Kotarou found Hazuki at the trash dump one day and took him into his home. It turned out that Hazuki was a Hybrid Child, a doll that grew and developed in response to its owner's love and attention. Experience Nakamura-sensei's stories of earnest, pure love in this three-part series, including a never-before published short and extra!!