Again, where is the problem? If you want to send money to your child on their birthday, just send it. Why do you need a contract, 'smart' or otherwise, for that?

Edit: What's funny about that thread is that it's someone asking for help to get a contract written (...like you do when you see a lawyer), and there's supposedly (or not, unsure about the sarcasm) a venerability in the contract itself.