Natural Born Subject (NBS) was never the same as Natural Born because the usage of term NBS also includes naturalized Subjects.
Gray who wrote the 1898 WKA opinion quoted (dicta) the famous jurist Blackstone, but he did inform the uninformed that the British NBS law was of British statute or regulation and that it was not natural law. Blackstone who in his published "Commentaries" completely agreed with deVattel that Natural Born and Natural subject are NOT the same.
The difference between a natural born subject and a natural born citizen is one of being either a free citizen or the subject of a sovereign.
The issue is what it takes to be natural born - and there was OBVIOUSLY no requirement under English law that one be born in England of English parents to be a natural born subject.
But one who was naturalized, as a subject OR as a citizen, WAS NOT natural born. The origins of the word naturalization was that it would confer the state of natural allegiance that otherwise had to be granted through the natural act of being born.
One is either natural born or naturalized.
Do you think women have a natural law right to participate on and equal footing with men in representative government?
Where did that natural right come from? Was it always there and only recently recognized - or is it an unnatural impulse to allow women to participate in representative government?