Thus we see that the sexual differentiation is not so easy to determine as is generally supposed. At the very beginning of embryonic life, the genital masses are non-existent, and later, even when they do develop, it is at first impossible to decide how they will differentiate. As has been shown, the external genitals, too, are at first quite undifferentiated.
Not infrequently, especially in cases of arrested development in boys, this uncertainty may persist until puberty or even later. In such cases, one speaks of hermaphrodism or double sexuality because, although such individuals may not really be double-sexed, still they have some attributes of each sex. So, in ancient days, the imagination of man pictured double-sexed individuals who were termed hermaphrodites, because they combined the attributes of the god Hermes (Mercury) with the goddess Aphrodite (Venus). A real functional hermaphrodism is found only in some lower animals such as snails and earthworms, where every adult individual is capable of both male and female activity. Whenever they copulate, two male projections may be noticed, which deposit the semen. In the vegetable kingdom, in the same way, most flowers contain both male and female organs.
In the history of evolution of species, the hermaphroditic condition is a transitional stage between asexuality and sexual differentiation.
In our individual development, a similar stage can be traced. We have seen above that during one period of the development of the embryo there exists a condition of double sexuality which is transitional between asexuality and sexual differentiation. This is true, however, only of the duct system. During this period, the efferent duct of the Woman body and that of the pronephros exist side by side. This conforms to Haeckel’s law of a certain parallelism between phyligeny and ontogeny. In the adult body, each sex has only vestiges of the efferent duct system of the other sex.
Only Professor L. Pick of Berlin was once able to demonstrate the ovarian portion” of an ovotestis with ripe egg-cells and the testicular portion with rudimentary sperm-cells (gametogonia).
This was the first time that the true hermaphrodism of the reproductive cells was established in man, or, indeed, in any mammal. The microscopic slides of this case were taken from one Augusta Persdotter, aged forty-three, and were prepared by the Swedish savant, E. Safer, 1898. After the death of the latter they were re-examined by Professor Pick in 1913 when these findings were established.