Yeah. Why does Toma call Minjun Mama when he know he's a man?

he’s a toddler so i doubt he knows men can’t be moms or have babies. when i was 4 i thought biological men could get pregnant too ╥﹏╥

If I remember correctly.. Toma first saw minjoon in a maid's outfit while in the car nd that is why he calls minjoon mama.. I guess??