The fuller answer
School forms, family trees, parent events, introductions, and casual questions often assume one family structure. A young person should not have to disclose foster care, adoption, incarceration, death, addiction, immigration, LGBTQ+ parents, or housing instability to complete an ordinary assignment.
Different situations need different answers: a short public boundary, a practical answer for a teacher, and a fuller private explanation for a counselor. Choosing less detail is not lying.
Schools can often adapt assignments and contact systems when an adult clearly explains what is needed. Privacy should be balanced with giving responsible staff enough information for safety and logistics.