As far as I know the quality of Jack Russell hair is no worse for babies than other dogs - however the quantity of hair can be a problem, as Jack Russells do shed quite a bit.
Besides that, Jack Russells are really not suitable for children under the age of 5 or 6 years old. Young children don't understand that they need to give a dog space sometimes and they aren't good at picking up the dog's body language.
For a Jack Russell, this can be a problem - a baby or toddler might think they're just playing, but the dog might view their actions as a threat and, in some cases, react aggressively if pushed too far. If you have a baby I strongly recommend you don't get a Jack Russell.
