In the embryo, the cortex is derived from the same patch that gives rise to the sex organs, the ovaries in the female, and the testes in the male, described as the germinal epithelium.

It was in 1849, that A.A. Berthold of Göttingen, a quiet, sedate lecturer, carried out the pioneer experiment of removing the testes of four roosters and transplanting them under the skin.

Now, as the experiments of Steinach upon the transplantation of ovaries into males deprived of their testes and of testes into females deprived of their ovaries have demonstrated, the removal of the interstitial cells of one sex assists enormously in arousing the opposite sex traits that have been latent, homosexuality.

The mixed ensemble of the directly contrasting type, such as the concomitance of testes with feminine secondary sex traits, or of ovaries with masculine sex traits, have been described from time immemorial as freaks.