A childhood belief about giving birth

When my son was 5 my sister had just had her first child. I have always been open with him about things in an age appropriate manner. Well he wanted to know how my nephew had gotten out of my sister. He loved animals so he had seen shows with animal live births but the concept of a human birth was hard to understand. I tried to say there was an opening that got bigger and that is how the baby got out. He didn't understand so I said it was like a door. He thought I meant an actual door like to his room. That confused him all the more. So I told him it was like a hole that would get bigger and the baby came out that way. This satisfied him & so ended our conversation. So a few weeks later his pre-school class was making construction paper butterflies out of heart shapes & pipe cleaners. They were glueing the pointed part of the heart together for the body, the pipe cleaner for the antenna the hump part of the heart was the wings of the butterfly. Well my son was glueing the bumps together and that was leaving an opening. So his teacher, who is pregnant & due any day, is pointing this out to him, that his butterfly will have a hole in it. He looks at her and calmly says "Well, that's where the babies come out". I worked in the same pre-school & she came & got me immediately to tell me. We laughed so hard we had tears in our eyes & it very nearly sent her into labor. I guess that's what I get for being honset with my kid :)