Fear of children is called pedophobia not to be confused with pedophilia because the words look similar.
Pedophobia is the fear of infants, children, babies and young children and there's really no known exact cause that makes some people fear small children or babies but it has been suggested that the fear of babies and children is because Children can embarrass us because they point ever too cleverly and clearly to our denial of personal, material, and maternal history.
I have a friend who fears young children and babies and will not even hold a baby and she just doesn't understand why either and she's been trying get over it.
She doesn't hate children or babies but just fears them and gets nervous around them.