Baptists
In 1609, while still there, Smyth wrote a tract titled "The Character of the Beast," or "The False Constitution of the Church." In it he expressed two propositions: first, infants are not to be baptized; and second, "Antichristians converted are to be admitted into the true Church by baptism." Hence, his conviction was that a scriptural church should consist only of regenerate believers who have been baptized on a personal confession of faith. He rejected the Separatist movement's doctrine of infant baptism (paedobaptism). Shortly thereafter, Smyth left the group, and layman Thomas Helwys took over the leadership, leading the church back to England in 1611. Ultimately, Smyth became committed to believers' baptism as the only biblical baptism. He was convinced on the basis of his interpretation of Scripture that infants would not be damned should they die in infancy.

Q: Smyth believed a scriptural church should consist only of regenerate believers who have been what?
baptized on a personal confession of faith