If you are a teacher, do not ask your students to make a family tree as a school assignment. *Especially* do not do this as a class art project to be posted on the wall.
A lot of kids have very complicated families, and complicated feelings about which words to use for which people.
For instance: Some kids call multiple people “mom”. Sometimes this is because they’re being raised by a lesbian couple. Sometimes this is because they are adopted and also maintaining a relationship with their mother who gave birth to them. Sometimes this is because their parents divorced and remarried and they also see their stepparents as parents. None of these relationships map easily onto a family tree project.
Some kids don’t have any parents at all. This isn’t something that they should have to tell their peers if they don’t want to.
Some kids aren’t sure who their parents are. Is it the people who adopted them when they were a baby and disrupted when they were six? The person who gave birth to them? The people they’re living with now? The one nice staff in their group home? The person they’re in foster care with who they’re hoping will eventually adopt them? It’s complicated and not ok to ask kids to declare this in writing in front of everyone.
There are any number of emotionally fraught and complicated situations that go along with describing families. It’s not good to have kids do that as part of an assignment, unless you’re working in a context in which getting people to do emotionally fraught things is appropriate.