How Many Moms until a Dad?

I think my wife and I split duties 50/50, or at least as well as we can. I often cook and clean, take my kid to school, and my wife does the rest. We are both satisfied with out duties, but whenever my kid needs anything he almost always asks for "mom." I feel like he switches to "dad" after at least 5 moms lol. I think it annoys my wife to no end, and I completely understand. I'll be sitting next to him and my wife will be in another room and he'll ask for mom to get him milk--dude, I'm right here haha. Anyone else experience this? My poor wife. Mom, Mom, Mom, Mom, Mom.....Dad.