Mommy is the Best Daddy in the Whole World
Please accept my condolences on behalf of all the new parents who are staying home with their children right now. The person who takes care of the baby the most and spends the most time with him or her at home will usually become the child’s main attachment figure. That is something that affects everyone in the same way. If someone has a bigger impact on you, you are more likely to remember their name. This also works the other way around.
This kind of chance comes up during childhood when most kids don’t have any ideas about how men and women are supposed to act. When people are young, before society and gender norms start to hold them back, their individuality shines through in all its glorious variety. Baby refers to his parent as both “Mommy” and “Daddy” because he understands that both names refer to the same person.