Fleas can be mildly dangerous to babies and children because they may bite them in order to obtain blood, causing an allergic reaction which results in red and itchy bumps similar to mosquito bites.
These bites run the risk of becoming infected if they are scratched and the skin is broken, and are also quite bothersome and uncomfortable for the victim.
No species of flea specifically targets humans as hosts, but they may bite them if there are no other suitable food source is available.
If your home has flea infestation it is probably caused by an animal living in the residence, such as a dog or cat. In order to protect them as well as the people in the household, is advised to use a suitable over-the-counter medication such as Frontline to get the flea infestation under control.
These medicines kill the adult fleas before they are able to reproduce, effectively eliminating the lifecycle of the flea. Once their primary host, the cat or dog, has been treated, the fleas will disappear and not harass any babies or children in your household.