Ernest Rumley Dawson.

The causation of sex in man; a new theory of sex based on clinical materials together with chapters on forecasting or predicting the sex of the unborn child and on the determination or production of either sex at will online

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HAVING explained the production of single births by means
of my theory, it remains to see whether the theory will
equally well explain the production of plural conceptions,
twins and triplets, etc.

In looking for an explanation of the occasional birth of
more than one child, we must not forget that, to quote
Play fair* " Plural births must not be classified as natural
forms of pregnancy," or, as Garrigues* says, "Multiple
foetation must be looked upon as an abnormal event."


As regards the origin of twins, there are four ways in
which they arise.

Variety A. 2 G. Fs., 3 2 ovaries, 2 ova, 2 sexes.

In these cases each ovary matures a G. F. at or about the
same time, so that we get one G. F. with an ovum each from
each ovary, therefore the foetuses are of opposite sexes, one
male, one female.

Play fair says :

" In the largest number of cases of twins the children are of
opposite sexes."

Spiegelberg, Pinard, Simpson, and Berry Hart, all confirm

Veil, 4 quoted by Lusk, found in 150,000 cases of twins,

1 Playfair, op. cit., vol. i., 1898.

2 Garrigues, "Text-book of Obstetrics," 1902, p. 258.

3 G. F.=Graafian follicle.

* Lusk's " Text-book oi Midwifery," 1889, p. 230.

I 3 2


in 54,000 the children were boy and girl, in 50,000 they were
both boys, and in 46,000 they were both girls.

Churchill?- out of 1,321 cases of twins, found there were
495 cases of boy and girl, 416 cases of two boys, while 409
were cases of two girls.

Rumpe, quoted by Jewett, " Practice of Obstetrics," 1899,
p. 296, found in 101 cases of two-egg or binovular twins,
54 were boy and girl more than half, 31 both boys, and
16 both girls.

This marked preponderance of cases of boy and girl twins
over twin boys, or twin girls, must have its definite cause,
and they are necessarily of opposite sexes because the two
ova come from opposite ovaries. And these cases of
different sexed twins are necessarily most numerous, because


Hence we find that an ovum from each ovary is fertilised
at, or about, the same time, more often than are two ova
from the same ovary; but opposite sexed twins are the
commonest, therefore we are justified in saying that opposite
sexed twins are due to the opposite ovaries ovulating almost

There would be a corpus luteum in each ovary. It is in
this variety of twins that we most often find two separate
and distinct placentae ; they may, however, be fused together.

This is the only mode of origin of different sexed twins.

Variety B. 2 G. Fs. from 1 ovary, 2 ova, 1 sex.

Here the children are of similar sex, either two boys or
two girls.

They are derived from two G. Fs. from one or other
ovary; each G. F. contains a single ovum. In these cases,
which are not so common, we find (instead of each ovary
supplying an ovum) one ovary alone will supply two Graafian
follicles, so that two ova are derived from the same ovary,

1 Churchill, " Midwifery," 1866, 5th ed. p. 482.


and therefore the twins are the same in sex, either two males
or two females, according to which ovary the ova came from.
Play fair (op. cit., p. 184) says:

" The most common cause of multiple pregnancy is probably the
nearly simultaneous maturation and rupture of two G. Fs., the
ovules being impregnated at or about the same time."

This therefore applies to both the varieties A and B.

The birth of both a dark and a light child to a negress
is possible only in one or other of the above two varieties.

Birnbaum described a case of twin pregnancy where post
mortem the left ovary contained two corpora lutea, but no
sex was given.

In the following conclusive case two corpora lutea were in
the right ovary, the right Fallopian tube had burst and a
foetus had escaped ; its sex is not given, but I have elsewhere
shown that a foetus in the right tube and corpus luteum in
the right ovary means a male gestation. The uterus con-
tained another foetus, a male.

" New Sydenham Society Year Book," 1862, p. 339,
quotes the following:

" Tuffnell's case. Patient pregnant between three and four
months. Post-mortem. Three or four quarts of fluid and clotted
blood were found in the abdomen with a small foetus floating therein.
There was a rent in right Fallopian tube, and a cyst from where
the foetus had escaped. Right Fallopian tube and ovary agglutinated.
Foetus one inch long. The uterus contained a healthy male foetus
proportionate to the date of conception. The cystic cavity in the
right Fallopian tube contained a solid organised mass like a miniature
placenta. There were two distinct corpora lutea in the right ovary"

This case proves a twin male pregnancy, with both ova
coming from different Graafian follicles, but from the same
ovary, the right. Hence the same sex, and that male. One
foetus had developed in the right tube, the other in the
uterus. It was a combined Extra- and Intra-uterine male

In this variety of twins the placentae may, or may not,
be fused or grown together, and though there are often two
quite distinct placentae, I have found a single fused placenta
(showing evidence of the amalgamation of the two original
placental areas) in a small majority of my cases.


Variety C. 1 G. F., 1 ovary, 2 ova, 1 sex.

In this variety the children are of the same sex. One or
other ovary supplies the single G. F. which happens to
contain two ova (cf. K, Fig. 8, p. 17); the sex will be
identical, but will depend on which ovary supplied the G. F.
Play fair' 1 says:

" It may happen that a single follicle contains more than one
ovule, as has actually been observed before its rupture."

This anatomical fact has the support of Lusk 2 and Hirst, 3
who reproduce a drawing of Waldeyer's showing the two
distinct ova in a single G. F. Its occurrence is also admitted
by Pier sol, 4 Berry Hart, 5 and Whitridge Williams.

In these cases only one corpus luteum would be found in
one or other ovary, although two children were born. This
fact was distinctly pointed out by Montgomery, 6 who says.

" A vesicle may contain two ovules, in which case twins may be
accompanied with only one corpus luteum."

The children in this variety will more closely resemble
each other than in Variety B.

Variety D. 1 G. F., 1 ovary, 1 ovum with 2 nuclei, 1 sex.

The children are of the same sex; because they have
arisen from a double nucleus or germ-bearing ovum derived
from one or other ovary, they will be very much alike.
This variety thus differs from the former, as the single
G. F. contains but a single ovum, but that ovum contains a
double germ or germinal vesicle (as is common in fowls'
eggs) (cf. H, Fig. 8, p. 18) ; we thus get the so-called unioval,
homologous, or identical twins, which are stated to be seven
times more rare than other forms, and we find them not
only always alike in sex (which fact Schroeder pointed out long
ago), but sometimes joined together. Play fair (p. 186) says:

" Conjoined twins must of necessity arise from a single ovule
with a double germ, and there is no instance on record in which they
were of opposite sexes."

1 Playfair, op. cit., p. 185. 2 Lusk, op. cit., p. 37.

3 Hirst, op. cit., p. 54. * Piersol, op. cit., p. 143.

5 Berry Hart, " Guide to Midwifery," p. 247.

Montgomery, " Signs and Symptoms of Pregnancy," ist ed., 1837,
p. 231.


This should, I think, help to prove my theory, by showing
that one ovary always " breeds true." That is, ova from
one ovary only produce one sex. The children's hair will
always be the same colour when derived from a single ovum,
whether the twins are conjoined or not. Undoubted
examples of ova with double germs or two nuclei have been
reported, and are now admitted to occur by most authorities.
Norris and Dickinson 1 reproduce a drawing of Von Herff's
showing two well-marked nuclei in one ovum, and Whitridge
Williams 2 ' figures a good example, the two germinal vesicles
or nuclei being distinctly separated in the ovum; while he
states that " the existence of such ova (containing two dis-
tinct germinal vesicles) is indisputable."

Dr. T. Wilson 3 says :

" There is a much greater predisposition to the occurrence of
hydramnion in cases of twins derived from a single ovum than in
the commoner variety of twins developed from separate ova.

" The unioval variety of twins is of interest for many reasons.
The foetuses are always of the same sex, and are much more alike
than are those developed from different ova. They have a single
placenta, in which an anastomosis takes place between their vessels ;
acardiac monsters are generally admitted to arise only in this
variety of pregnancy."

Some cases of twins from a single ovum possibly all
the acardiacs are believed to arise, not from double nuclei
in an ovum, but by splitting or division into two of a single
nucleus, though no one has seen such an occurrence; but
single nuclei have been seen to contain two nucleoli or germinal
spots, as in a specimen figured by Nagel in Play/air's
" Midwifery "; so it is possible that, division of the nucleus
being purely supposititious, is not necessary, if it occur at all.

It must not be supposed, if two G. Fs. rupture, and two
ova are discharged, that they are sure both to be fertilised;
even if both be fertilised, one may easily die in the uterus.
Play fair 4 says :

" This is proved by the occurrence of cases in which there are
two corpora lutea with only one foetus."

1 Norris and Dickinson, " American Text-book of Obstetrics," 1897,
p. 71.

2 W. Williams, op. cii., p. 327.

3 " Trans. Obstet. Soc.," 1899, p. 237.

4 Playfair, op. cit., p. 184.


This is confirmed, as pointed out by Montgomery, 1 by
many authors, and by its occurrence in domestic animals.
In one case Montgomery examined there were " ten corpora
lutea in the ovaries of a sow, but only nine foetuses in the
uterus." After a diligent search " the remains of another
foetus which had been blighted " was found. I have
practically proved the truth of this with rabbits.

The explanation of the development of the second corpus
luteum in the absence of the second foetus is that the
presence of one foetus is quite sufficient to cause both corpora
lutea to develop into true corpora lutea.


From the foregoing particulars we see that as regards
their sex twins occur in the following order of frequency :

A. Boy and girl twins.

B. Boy and boy twins,
c. Girl and girl twins.

The first variety are known as pigeon-pair or different
sex twins, and occur most often; B and c, consisting of
children of different sex, are usually classed together as
same sex twins, and if so added together these two varieties
of same sex twins outnumber (as we should expect) the
first variety, or twins of different sex.

Variety B are more numerous than c.

It is necessary to point out very clearly this misleading
inclusion of children of different sexes under the heading
of " same sex twins," as astonishing errors and discrepancies
appear in some text-books as to the relative frequency of
the sexes in twin births.

We see, therefore, that different sex twins are more often
born than either 2 boys or 2 girls, but add together the twin
boys and the twin girls and call them " same sex " twins,
then this combination of boys and girls together outnumber
the cases of boy and girl twins that is, though different
sex twins are most often born, yet same sex twins are most
numerous !

1 Montgomery, op. cit., p. 230.


Here I may notice an objection raised by a reviewer,
who imagined that boy and girl twins disproved my theory;
for, said he, it showed that the ovaries did not always
ovulate alternately, but that both ovaries must in these
cases have acted at one and the same time. Quite so. I
have certainly not said they always did act alternately,
but they do usually, normally; and when they exceptionally
ovulate simultaneously, we get the unusual or exceptional
condition of different sex twins provided both ova be
fertilised, which, of course, does not always occur.

Boy and girl or different-sex twins, then, are evidence
of simultaneous ovulation by both ovaries. See the cases
of twins in detail described in Chapter XXIII. , pp. 191-194,
showing which ovary acted " out of its turn."

TRIPLETS. It will be quite easy to understand how
triplets occur from what has been said about twins, and how
triplets follow the same rule as to their sex. Usually one
ovary gives rise to twins, and the other to a single birth.
In this case two of the children are alike in sex. If the
children are all of the same sex, one or other ovary provided
them all, one G. F. providing either two ova, or else one
ovum with a double germ, and the other G. F. supplying a
single ovum; though one ovum may rarely give rise to all
three children uniovular triplets.

W. Williams 1 says:

" Occasionally two, and sometimes three, distinct ova may be
found in a single follicle, and it is from such structures that multiple
pregnancies not infrequently develop ";

so that one corpus luteum only may be found in a case of
triplets of the same sex. The case described by Saniter 2
would have been such an example had it been possible to
have examined the ovaries, for the triplets were all males,
derived from a single ovum, and there was only one placenta.
I have not been able to find a report of a case of three
corpora lutea of pregnancy discovered in one and the same
ovary; but probably the cases described by Dr. H. R.
Spencer 3 and by Dr. G. Bate in the " Lancet " would each

1 Williams, op. cit., p. 63.

2 Saniter, " Brit. Med. Journ.," Epitome, March 30, 1901.

3 Dr.H. R. Spencer, " Trans. Obstet.Soc.," vol. xxxv. 1893, pp. 107-110.


have shown three corpora lutea in the left ovary, for the
triplets were " all girls, and there were three separate
placentae " in both cases.

G. W. Thompson 1 records a case of triplets a double
female monster and a single male child:

" The single male child was born first, was still-born, and had a
separate placenta and membranes. The sex was female of the united
foetus, which had two heads, four arms, and four legs, and two bodies
united by the thoraces."

It is practically certain that the female monster came from the
ovary opposite to that from which the single male child did.

Dr. W. Krusen 2 of Philadelphia has described a case of
triplets in the right Fallopian tube. They were of only
two months' development, and no sex was given. Compare
also Dr. Russell Andrews' case of male twins in the right
Fallopian tube (p. 71).

Triplets follow the rule of twins that owing to the
rather larger right ovary there are more boys than girls
produced, the commonest occurrence being 2 boys and i
girl, this combination being twice as numerous as any other
combination. Freureisz, 3 in over thirty years' experience,
met with four cases of 2 boys and i girl, but only one case
of 2 girls and i boy. It therefore corroborates and explains
the statement of Saniter quoted by Williams, 4 that " in
triplet pregnancy the children are usually derived from two
ova one from one, and two from the other " because
twin boys from one ovum are far commoner than twin girls
from one ovum; and a case of triplets in a colleague's
practice bore this out, the two boys being uniovular twins,
and the girl was from a different and distinct ovum from,
I maintain, the opposite ovary.

Compare the case of triplets described in the note on p. 145.

Dr. Voron 5 describes a case of triplets with two girls and
a boy, who was the last born. There were three distinct

" Indiana Med. Journ.," April, 1899.
" Brit. Med. Journ./' Jan. 1902, p. 43.

3 Freureisz, Gynaecologia No. 4, 1902.

4 Williams, op. cit., p. 327.

5 Dr. Voron in " Bull, de la Soc. d'Obstet. et Gynecol. de Paris," June,


cords inserted marginally into a single-looking placenta.
[< There was a bag of membranes for each foetus." In-
jection of the umbilical arteries with three different colours
showed " there was no vascular communication between
the placentae," " the coloured areas being distinct and
sharply limited." This therefore showed that the preg-
nancy was due to the fertilisation of three distinct ova,
" with subsequent fusion of the adjacent parts of the three
placentae." I should have expected two corpora lutea
in the left ovary, and one in the right.

Almost identical with the above was the only case of
triplets I have personally attended.

There were 2 girls and i boy, but with three separate
and distinct, not fused, placentae, each following its child's
birth. Here, too, three distinct ova had certainly been
fertilised I say two from the left ovary and one from the

QUADRUPLETS. If both ovaries give rise to twins, we
get quadruplets ; or if one ovary gives triplets and the other
a single birth, as in a case by Simpson, 3 males and i female.
Here the right ovary must have ruptured two G. Fs., one
of which contained two ova, or else had a double germ in
one ; while the left ovary supplied a single ovum only.

If all four children are the same sex, it is possible only
two G. Fs. are present, both G. Fs. containing two ova; or
one G. F. with two ova, the other G. F. having one ovum but
a double germ. If there were three G. Fs. the arrangement
is quite simple.

It is possible for one G. F. to supply quadruplets; the
children would be all the same sex. The G. F. would then
contain two ova, and each ovum a double germ.

The following case is very suggestive, from the appear-
ances of the placentae, of the origin from the two ovaries
of two ova each to form the quadruplet birth:

M. Etchecoin 1 reported a case of quadruplets :

" The mother had borne her first child nineteen months before
she was delivered prematurely, at the fifth month, of 4 infants '
2 males and 2 females. There were four placentae adherent in pairs."

1 " British Medical Journal," October 19, 1901, P- 1166.


The following case proves very decisively that the one
ovary produced the male child, and the other ovary the
three females:

Baudouin, in the " Paris Medical Gazette/' describes a
recent delivery of quadruplets, in which

" one ovum contained three foetuses, two of them forming a sterno-
pagus (i.e., were joined together at the chest), all of the female sex.
After their delivery a second bag of waters ruptured, and a still-born
male child followed."

There were thus two ova only.
Dr. Lloyd Roberts 1 reports a case of quadruplets

" all females. Placenta was single. Four cords were distinct. A
single chorion enclosed four amniotic sacs."

They were therefore derived from one ovum, and therefore
from one ovary I should maintain the left.

Dr. Clifford White 2 reports a case of 3 males, i female.
Two males were uniovular twins and stillborn ; the other boy
and the girl were alive. The males were born by the vertex,
the female by the breech. So the four children came from
three ova.

Dr. Nijhoff, 3 of Groningen (Netherlands), reports a case of
quintuplets 4 girls and i boy. Three of the girls were
derived from one ovum, and represented uniovular triplets ;
while the other girl, and the boy, arose from two separate

" The placenta consisted of one continuous cake. At the foetal
side five separate umbilical cords were inserted, each in a distinct
sac formed by the foetal amnion. Three of these sacs were enclosed
by a common chorion. The two others had a separate chorion."

This is direct evidence of fertilisation of three ova, and I
maintain the girls were derived from the left ovary and the
boy from the opposite one.

Baudouin, 4 in discussing SEXTUPLETS, brings out the fact
that, as in twin births, the number of boys far exceeds the
girls. Thus in one case all the six children were boys; in

1 " Journal of Obstetrics and Gynaecology," vol. iii. 1903, p. 91.
. 2 " Proc.^Roy. Soc. of Med.," January 1910, vol. iii., p. 79.

3 Ibid., July 1904, vol. vi. p. 32.

4 Ibid., vol. vi. p. 52.


another case 4 boys and 2 girls; while another was 5 boys
and i girl. Thus three cases give 15 boys to 3 girls !

It will thus be seen that plural pregnancies entirely sup-
port my theory; and no theory, such as either nutrition
theories; infrequency or frequency of intercourse theories;
or strong versus weak spermatozoon theories; or the relative
vigour theory, or even the relative age theory of the parents,
can possibly explain the occurrence of boy and girl or
" pigeon-pair " twins, to say nothing of triplets and quadru-
plets. This fact also disproved Schenk's hypothesis; for
if an ovum in a woman, whose urine through dieting habitu-
ally contained sugar, invariably developed when fertilised
into a girl, and the presence of that sugar rendered the birth
of a boy impossible, how could any woman be pregnant
with both a boy and a girl at the same time, or with two
of each ? In fact, a preliminary careful study of plural
pregnancy would have prevented many theories of the causa-
tion of sex ever being broached.

The varying arrangement of the foetal membranes, and
the fact that conjoined twins are always of the same sex,
are both only satisfactorily explicable by the present

Close study of plural pregnancy demonstrates clearly that
such an occurrence must be ascribed to the mother and not
to the father.

We know that many million more spermatozoa are pro-
vided every time (Lode estimated them as over 200,000,000
in a single ejaculation) than are necessary to simply fertilise
the normal single monthly provided ovum.

If, however, for some reason, probably anatomical, more
ova are regularly provided, we must expect plural preg-
nancies. Puech definitely alleges " superior development
of the ovaries " as the cause of the simultaneous develop-
ment of multiple ova, and here we may recall that a quite
healthy ovary has been found which measured 3f in. in its
long diameter, while the average is ij in. We should
expect that ovary to provide more than the normal, one
ovum at a time.

It is quite evident that, if the amount of ovarian tissue


capable of supplying ova is increased in amount, we must
expect an increased production of ova. So that unusually
large ovaries lead to an unusually large number of ova
being supplied, and this extra or " superior development "
of the sexual glands is in my experience undoubtedly
inherited; 1 there are, indeed, many reasons for believing
that this excessive uberty was formerly the rule, while the
degree of comparative infertility of modern woman is a
result of the constant repression of her natural instincts,
a sacrifice of her health on the altar of fashion and financial

Hellin, quoted by Whitridge Williams, 21 discussing multiple
pregnancy, states that " the ovaries of women who have had
a number of multiple pregnancies contain an excessive
quantity of ova." Accordingly, " the condition is probably
due to the maturation each month of several ova, instead
of one, as is generally the rule." And I here recall that
normally the right ovary is practically always a little larger
than the left, and thus, supplying rather more right or
male ova, we get the normally slightly higher birth-rate
of 106 boys born compared to 100 girls.

That it is the woman who is responsible for plural preg-
nancies is clearly shown by the following case reported by
Vortisch 3 : A woman by her second husband gave birth to
sextuplets, 5 boys and i girl; by her first husband she " had
previously given birth to twins, quadruplets, and triplets in
successive pregnancies." That is, 15 children in four
pregnancies. The maternal origin of multiple births is
thus evident, there being two different husbands.

This contention is borne out, too, by the cases we fre-
quently read of, the woman having twins, or other form of
plural pregnancy, repeatedly; thus Dr. Lloyd Roberts, 4 in
1893, related a case of a woman having twins fifteen times.
In my own practice the following cases have come under
notice: A woman, Mrs. M. McL., had twin boys seven times
over, besides four single male births i.e. 18 boys and oddly

1 It is comparable to the high egg-laying strains of fowls, for hens which

1 2 3 4 5 6 7 8 9 11 13 14 15 16 17 18

Online LibraryErnest Rumley DawsonThe causation of sex in man; a new theory of sex based on clinical materials together with chapters on forecasting or predicting the sex of the unborn child and on the determination or production of either sex at will → online text (page 11 of 18)