The stories may have:
Child protagonists (at least, the main character(s) are children in the beginning, before a time-skip.)
The main lead may be a nanny, caretaker, kindergarten teacher, babysitter, or something else that involves working with children.
The main lead might have younger siblings they're close to; they could have the same bio-parents, they can be half-siblings, adoptive siblings, step-siblings, or foster-siblings.
The main lead might be or become a parent; the main lead(s) could be a bio-parent, adoptive parent, step-parent, or foster parent. (I'll include stories where the main leads have children together in the end as well.) As long as there is parenting involved, I will also include stories with parents/guardians of kids that are in their teens (as in, below 18; minors).
I will also include stories where the main lead gets pregnant early on; stories about pregnancy will be included.