Why would you think that?

So I mention that I'm a stay at home dad and this person asks, "So you change her diapers?" I told them nope. Either I just let her sit around for 10 hours until the wife gets home or if it gets too stinky, I take her down to the mall and ask some nice lady to take the baby into the restroom to change her diaper - cause what's a dad know about diapers.