On A Peculiar Type of Intersexuality in the Guinea-Pig

Abstract

An abnormal condition of the external genital organs in 16 otherwise normal female guinea-pigs is described. They possessed an hypertrophied penis-like clitoris and horny styles similar to those in the intromittent sac of the normal male penis. The abnormalities are often asymmetrical, the clitoris and the horny style on one side being more developed than on the other. They may even be absent on one side. It is suggested that the malformation is a peculiar type of "partial somatic intersexuality," the external genital organs resembling those in the male guinea-pig. The condition is identical with that described in the castrated female guinea-pig experimentally masculinised by testicular transplantation. There was no indication of the ovaries producing simultaneously female and male sexual hormones: (a) The ovaries were histologically normal. (b) The ovaries when engrafted into castrated males produced the typical female hormonic effect on the mammary glands and had no influence on the penis or on the horny styles. (c) The clitoris and the horny styles of the intersexual females were not affected by removal of the ovaries, whereas in the male removal of the testes caused a pronounced regression of the horny styles even in fully grown animals. (d) The horny styles when cut regenerated even after removal of the ovaries; there is never a regeneration in the castrated male, but only in the normal male. The question is discussed whether the described type of intersexuality might be a case of "successive hormonic intersexuality," both kinds of sexual hormones having been produced simultaneously for a certain time whereas at a later stage only female hormones were secreted. The hypertrophied clitoris and the horny styles would then be considered as "fixed" sex characters persisting after the disappearance of the male sexual hormones. The problem of fixation of sex characters by sexual hormones is considered on experimental lines. The facts observed are rather against the suggestion that the intersexuality described is a case of successive hormonic intersexuality. Other possibilities of explaining the morphogenetic basis of this peculiar type of intersexuality are also discussed. The intersexuality described is of an hereditary nature.