Well I agree with the general beginner-herper age of two years old. However even at 12 weeks old on a field herping camping trip my youngest son "held" a wild Eastern Fox Snake on Pelee Island. haha
My kids are unpredictable at the best of times so when handling animals I need to take extra precautions to avoid damaging the animals. I don't have any animals that would currently pose a danger to my children (except maybe the ball python if I left him alone with it and it got wrapped around his neck...but really, that's not about to happen!).
With babies, I've held their hand closed around my thumb so they could feel the snakes with the backs of their hands...but they need to be washed like the other kids' hands as replied above to avoid contaminating themselves afterwards.
I think one of the most important and yet unmentioned aspect of children holding animals is that children may refuse if desired. I always state that they don't have to do it if they don't want to, to take the pressure off. Often a hesitant child will be inclined to give touching it a try after they see other kids interacting with the animal.
Another common concern for me is having my snakes stepped on (knock on wood!) so I encourage the kids to stand or sit still while handling. No running around and for goodness sake no scaring other kids (and especially adults) with the snakes!
It also helps if you know a little about the animal before you show a kid because some of them can give you a thorough examination! lol
haha Well BAZ, hope your daughter enjoys your water monitor!
Bj (mom to Christian-6, Samson-4, Henry-2, stepson Ben-7)