How do you know you've made an impact?

At this very moment, my daughter is sitting in her chair, her baby doll nursing under a nursing blanket "because she needs privacy, Mommy." My son may be the only two year old boy in the world who walks around pretending to have a baby in his belly. He's folded a baby doll in half and came to me, frustrated that he couldn't get her to stay under his shirt. I explained that when you actually have a baby in your belly, the desire is to get them out, not keep shoving them back in. He was adamant, though, and is now walking around glowing with pregnancy ;-).