- Mater semper certa est translationPater semper incertus est translation
These are tropes that have to do with paternity. If you get past the questionable paternity to actual parenthood, see The Parent Trope.
- Chocolate Baby: A supposed father is obviously not the biological father, because the baby looks very different.
- Daddy DNA Test: Science or magic are used to confirm paternity.
- Give the Baby a Father: A man who isn't the father of the child proposes to a pregnant woman, claiming fatherhood—if not paternity—of her baby.
- Law of Inverse Paternity: The possible father who would cause the most problems turns out to be the actual father.
- Luke, I Might Be Your Father: A character is disclosed as a possible parent.
- Mama's Baby, Papa's Maybe: Fathers (especially ones without DNA testing) cannot be sure of their children's paternity and must trust the mothers.
- Who's Your Daddy?: Unknown paternity causes angst and drama.