inborn character

It is impossible in the present state of knowledge to answer these questions satisfactorily, but the balance of evidence appears to favour the view that sex is an unalterable, inborn character.

From Encyclopaedia Britannica, 11th Edition, Volume 9, Slice 3 "Electrostatics" to "Engis" by Various

With plenty of elbow-room the Californian works out his own inborn character.

From California and the Californians by David Starr Jordan

The way in which she was throwing herself at Larssen during his absence for a few weeks was typical of her inborn character, which nothing could uproot.

From Swirling Waters by Max Rittenberg

A well-nourished mother, free from care and disease, may have a finer child than a half-starved woman, crushed by worry and work, but neither starvation nor nourishment alter the inborn character of the child.

From Epilepsy, Hysteria, and Neurasthenia Their Causes, Symptoms, & Treatment by Isaac George Briggs

It appears only in later life, but it is none the less an inborn character.

From The Story of the Living Machine A Review of the Conclusions of Modern Biology in Regard to the Mechanism Which Controls the Phenomena of Living Activity by H. W. (Herbert William) Conn