I must agree. I have succesfully created a Ghost baby. This is how I did it: One of my sims was a klepto and stole a gravestone from the cemetary. At night, the ghost came out and haunted my house. ( early hours before 6am.) I had the female sim flirt with the male ghost until it gave the option for "whoo hoo." I tried for baby instead. Once you hear the chime for pregnancy, then it is just a matter of time before you give birth to a ghost baby. This baby will behave like a normal sim, only it will look like a ghost. Once it gets old enough, you will be able to control it. In order for you to control a ghost without the baby making mechanics, you have to be a bit homicidal with sims. Find creative ways to kill your sims and you might get a call from the science lab. They will try to resurrect your sim, but instead will bring back their ghost and allow you to control it.