I doubt it tho but you won't truly know until they develop one. I assume your wife's impediment is related to a lack of oxygen and delayed developement in vocal motor skills... something like a physical delay of the growth of muscles (I'm not a specialist). I stutter and I don't know a single family member that does nor did I have any physical or physiological issues ( I know of) in my developmental stages to increase my likelihood of obtaining an impediment. I think your children will be a-ok 👍