What do you think of parents who let their children play with pets (the more traditional ones... dogs, cats and birds)? I think with due care and limitations, there is no problem at all. Children need to acquire biological immunity in some way during their growth, and this can be provided by animals in a healthy way. Everything just needs to be controlled. If you are raising a pet, it's supposed to be a clean, well-fed animal... Anyway, be a healthy animal, right? So, what would be the problem? P.S: With the exception of the child being allergic.