The child grows up in the sequel, "Love Kids."
Ch. 1 -> 1st Story ~ The child is the seme's; the child is from the seme's older sister who died.
The child is the uke's; the uke is taking care of his older sister child, his nephew
The uke was picking up his sister's child from daycare, his nephew
The child is the seme's biological son
2 children that are the same age; one was the uke's brother and the other was the seme's nephew (his older brother's child.
Kodomo x Otona no Houteishiki