No one is more cautious than a first-time parent. After our daughter was big enough to ride on the back of my bicycle, I bought a special carrier with a seat belt and got her a little helmet.
The day of the first ride I put her in the seat, double-checked all the equipment, wheeled the bike to the end of the driveway, carefully looked both ways and, swinging my leg up over the crossbar, accidentally kicked her right in the chin.