The words “two” and “parents” do not appear in the Constitution and the concept of two U.S. citizen parents being required in order to qualify as a natural born citizen has never been codified in a statute or in case/common law. One does not have to define "parents" when it comes to citizenship as it is axiomatic that a "citizen" cannot exist without parents. No one is "parentless." Your point is as if you asserted that "arms" doesn't presuppose the existence of bullets. The founders had no interest in wasting their time on things which are obvious.
And for the second part of your statement, that is also not true. Pennsylvania did indeed explicitly acknowledge their understanding that citizenship in their state was not based on English common law.
If Congress was to pass a bill and a president signed it into law or if the Supreme Court was to rule that two U.S. citizen parents are required in order to be a natural born citizen, I would be supportive, but that is not the case at this time.
The constitution cannot be amended by congress passing a bill and the president signing it.
My understanding is that Louisiana, basing its law on the Napoleonic Code was the only original state that didn’t base its law ( to some degree) on English Common Law.
Reception statute of Pennsylvania, 1777:
[[section]]1. “Each and every one of the laws or acts of general assembly, that were in force and binding on the inhabitants of thde said province on the 14th day of May last, shall be in force and binding on the inhabitants of this state, from and after the 10th day of February next, as fully and effectually, to all intents and purposes, as if the said laws, and each of them, had been made or enacted by this general assembly . . . . and the common law and such of the statute laws of England, as have heretofore been in force in the said province, except as hereafter excepted.
http://famguardian.org/publications/propertyrights/Precept.html
American common law
The United States and most Commonwealth countries are heirs to the common law legal tradition of English law. Certain practices traditionally allowed under English common law were expressly outlawed by the Constitution, such as bills of attainder and general search warrants.
As common law courts, U.S. courts have inherited the principle of stare decisis. American judges, like common law judges elsewhere, not only apply the law, they also make the law, to the extent that their decisions in the cases before them become precedent for decisions in future cases.
The actual substance of English law was formally “received” into the United States in several ways. First, all U.S. states except Louisiana have enacted “reception statutes” which generally state that the common law of England (particularly judge-made law) is the law of the state to the extent that it is not repugnant to domestic law or indigenous conditions. Some reception statutes impose a specific cutoff date for reception, such as the date of a colony’s founding, while others are deliberately vague. Thus, contemporary U.S. courts often cite pre-Revolution cases when discussing the evolution of an ancient judge-made common law principle into its modern form, such as the heightened duty of care traditionally imposed upon common carriers.
Second, a small number of important British statutes in effect at the time of the Revolution have been independently reenacted by U.S. states. Two examples that many lawyers will recognize are the Statute of Frauds (still widely known in the U.S. by that name) and the Statute of 13 Elizabeth (the ancestor of the Uniform Fraudulent Transfer Act). Such English statutes are still regularly cited in contemporary American cases interpreting their modern American descendants.
However, it is important to understand that despite the presence of reception statutes, much of contemporary American common law has diverged significantly from English common law. The reason is that although the courts of the various Commonwealth nations are often influenced by each other’s rulings, American courts rarely follow post-Revolution Commonwealth rulings unless there is no American ruling on point, the facts and law at issue are nearly identical, and the reasoning is strongly persuasive.
Early on, American courts, even after the Revolution, often did cite contemporary English cases. This was because appellate decisions from many American courts were not regularly reported until the mid-19th century; lawyers and judges, as creatures of habit, used English legal materials to fill the gap. But citations to English decisions gradually disappeared during the 19th century as American courts developed their own principles to resolve the legal problems of the American people. The number of published volumes of American reports soared from eighteen in 1810 to over 8,000 by 1910. By 1879 one of the delegates to the California constitutional convention was already complaining: “Now, when we require them to state the reasons for a decision, we do not mean they shall write a hundred pages of detail. We [do] not mean that they shall include the small cases, and impose on the country all this fine judicial literature, for the Lord knows we have got enough of that already.”
Today, in the words of Stanford law professor Lawrence Friedman: “American cases rarely cite foreign materials. Courts occasionally cite a British classic or two, a famous old case, or a nod to Blackstone; but current British law almost never gets any mention.” Foreign law has never been cited as binding precedent, but as a reflection of the shared values of Anglo-American civilization or even Western civilization in general.—Wikipedia