I am going to create a private vanilla server.
When your child turns 1, you can upload your child's birth certificate. A level one character will be created on the server. The character will ONLY level when your child ages. So when your child turns 10, the character will also be level 10. If your child is ugly, it will become a horde. If not, it'll be an alliance character.
At the age of 60 they'll probably be close to retirement age so they can raid and enjoy the end game.
In the unlikely event your child dies before 60, every item the character carries will be auctioned for real money and I will be taking a fair 35% cut.