Ve CONG. INTERN. REPROD. ANIM. INSEM. ARTIF., PARIS, 1968, VOL. lI

acted as a trigger to a chain reaction which has greatly influenced
contemporary attitudes in modern endocrinology and immunology.
There is no reason, therefore, to belittle studies on intersexual
phenomena in domestic mammals. In fact there may be other basic
problems which can be studied in these naturally occurring cases
in the same way that the classical patterns in endocrinology and
neurology developed earlier in this century. For example,
Biggers and McFeely (1966) pointed out that studies of inter-
sexes in goats and pigs, show that most are genetic females with
no Y chromosome and yet they always develop testes. Studies on
mice and men, in contrast, indicate that the development of the
testes is dependent on genes carried in the male Y sex chromo-
some. The resolution of this paradox between the two groups of
mammals must surely advance our understanding of the genetic
control of sexual development.

The purposes of this paper are to: (1) list the causes
of intersexuality in domestic animals whose karyotypes are
known, and (2) briefly discuss special problems in animal re-

production which need further study by cytogenetic techniques.

SOME DEFINITIONS
The terminology used in an earlier paper (Biggers and
McFeely, 1966) will be retained in this review. Cases of inter-
sexuality may arise in three primary ways:

(a) Aberrations of known genetic and chromosomal origin,

(b) Aberrations of gonadogenesis,

(c) Reversal of the sex of the accessory genital organs.