How Do YOU Know My Mommy is Pregnant?!

I picked the kids up from daycare yesterday and as I was getting the kids situated in the car...a car pulled up into a space close to ours. So, our car, then empty space, then new car. It was one of the father's picking up in the car...he got out, looked at me, smiled and said "Hi". He went on to fix the car seat in his car and I went on to get Henry buckled in. Both the doors of the mini van were wide open as I usually get Henry in first and then buckle Luke in. So, the man asks, "So, when are you due?" I told him September and he smiled and said, "Congratulations". He went on to fix the car seat in his car. Meanwhile, Luke gives me a completely puzzled look and in the lowest voice that a 4 year can possible reach (this would be "normal" voice but you could tell he was trying to whisper), he asks, "Mommy...how does that man know that you are having a baby?" I stared at him for a second, reminded myself that he was four and said, "Son, do you see mommy's belly sticking out?" He nodded, yes. "Well, he sees it too and that's how he knows mommy is pregnant." He looks at me in complete disbelief...cups his hands around his mouth and shouts to the man very loudly, who is now almost at the daycare door, "HEY!...Hey!" The man turns around, Luke screams, "How did you know my mommy is having a baby?!" It all happened so fast. I said, "Luke!" The man opened the door, smiled really big, laughed and yelled back, "Because your mommy looks like she's having a baby." He scurries into the building...horrified, I'm sure. I am standing there with my mouth wide open...horrified, for sure. Luke looks me right in the eyes and says in complete astonishment, "You were right mommy." I said, "Son, I'm the mommy and I'm always right."