I can recall one game of D&D growing up that got a bit out of hand. The Dungeon Master got mad because we said the game was lame and started to throw dice at us all. A D20 to the gonads is no fun indeed. I think what we needed were these soft dice.
It’s a set of seven that can do just about anything you need in a game of D&D. The set has a d4, d6, d8, d10, d20, and a percentile d10. The dice are made of foam, and seem to be similar to a stress ball from the description. Each is about 2-inches in diameter.
These might be a good way to introduce your little one to D&D. Plus you can use them to determine the percentage chance that your kid can eat ice cream for dinner. The entire 7-die set is $19.99 at ThinkGeek. Now that I think of it, a giant foam die to the nads will probably still hurt, so wear a cup.