natural-born (adj.)

c. 1300, naturel, "of one's inborn character; hereditary, innate, by birth or as if by birth;" early 14c. "of the world of nature (especially as opposed to man)," from Old French naturel "of nature, conforming to nature; by birth," and directly from Latin naturalis "by birth, according to nature," from natura "nature" (see nature).

Of events, features, etc., "existing in nature as a result of natural forces" (that is, not caused by accident, human agency, or divine intervention), late 14c. From late 14c. of properties, traits, qualities, "proper, suitable, appropriate to character or constitution;"  from late 15c. as "native, native-born." Also late 15c. as "not miraculous, in conformity with nature," hence "easy, free from affectation" (c. 1600). Of objects or substances, "not artificially cultivated or created, existing in nature" c. 1400. As a euphemism for "illegitimate, bastard" (of children), it is recorded from c. 1400, on the notion of blood kinship (but not legal status).

Natural science, that pertaining to physical nature, is from late 14c.;  natural history meaning more or less the same thing is from 1560s (see history).  Natural law "the expression of right reason or the dictate of religion inhering in nature and man and having ethically binding force as a rule of civil conduct" is from late 14c. Natural order "apparent order in nature" is from 1690s. Natural childbirth is attested by 1898. Natural life, usually in reference to the duration of life, is from mid-15c.; natural death, one without violence or accident, is from mid-15c. To die of natural causes is from 1570s.

Old English boren, alternative past participle of beran (see bear (v.)). The -en of the Middle English past participles tended to drop the -e- in some verbs, especially after vowels, -r-, and -l- , hence also slain, etc., Middle English stoln. "In modern use the connexion with bear is no longer felt; the phrase to be born has become virtually an intr. verb" [OED].

It is attested from early 14c. as "possessing from birth the character or quality described" (born poet, born loser, etc.). It is from 1710 as "innate, inherited;" the colloquial expression in (one's) born days "in (one's) lifetime" is by 1742.  The distinction of born from borne (q.v.) is 17c.