Read the constitution: all the founding fathers, and all those who were citizens at the time of the constitution, are automatically grandfathered in as "natural born citizens." That clause ceases for anyone born thereafter.
Only eight of the founding fathers were immigrants. The rest were born on this soil. Four (Butler, Fitzsimons, McHenry, and Paterson) in Ireland, two (Davie and Robert Morris) in England, one (Wilson) in Scotland, and one (Hamilton) in the West Indies