A Natural Born Citizen is an unique class of citizen. It is a person born in the U.S. of two U.S. citizen parents. If I were a citizen of the U.S. and my wife was a Kenyan citizen, and our child was born in Kenya while we were vacationing in Kenya, our child would not be a Natural Born Citizen. Our child would still be a U.S. citizen.
That’s correct, assuming the conditions for naturalizing the child were met.
Provided that the citizen parent (that would be you, in the hypothetical you provided) AND your offspring born abroad under those circumstances met the residency requirements written within 8 U.S.C 1801.
Prior to the time window available for the offspring to meet the U.S. residency conditions, your offspring would of course be citizen of the United States, at birth according to the laws if the United States -- yet having derived their citizenship not from the laws, but from yourself under conditions stipulated by law.
To retain that status, in order to prevent there being citizens of the United States not raised as resident within the U.S., yet as "citizen" themselves and (thus conceivably at some later time able to pass on their own U.S. citizenship to those born overseas with no connection to the Nation's soil) Congress chose to legislate U.S. residency conditions which must be met --- of else children born to a citizen parent would LOSE the citizenship status they were born with.
It's as if -- the "naturally" a citizen jur soli component (of the soil, within the territory of) of qualification for citizenship at birth is recovered through returning residency (the parent returning to the U.S. with child, the child to a large degree raised within the U.S.) thus at all times the child be a citizen up until and following ever after when those residency requirement conditions have all been fulfilled.