In 1674, Mary of Modena the wife of James, duke of York as he was known then suffered a miscarriage. If instead of delivering a miscarriage she’d had a surviving son, named either Charles or James, what would have changes? One assumes the boy would be raised Anglican per his uncle the kings orders, which leads to some interesting things once James ascends the throne as James II in 1685. Would James try to convert his son to Catholicism? Would the boy convert or remain Anglican? Would the exclusionists want James removed and replaced by his son in the succession?
And with the kid being like his uncle instead of his father, in political terms what could this all do?
And whom might he marry? A French Orléans bride perhaps?