Descendants of Adam and Eve
Mulling over the idea of Adam and Eve and how everyone else after their children came to be, were their grandchildren products of incest?
With the creation of only Adam and Eve, marriage between close relatives was a necessity in the beginning of time.
As world population increased, that necessity disappeared, and in time God prohibited sexual relations among family members (Leviticus 19).
Since spouses in those early marriages were unavoidably closely related, we would not call children from those early marriages “products of incest.”