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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to compensate for the greater mortality of males.

This excessive male mortality, as we shall presently see,
does not only occur at birth.

At birth the difficulties and dangers of parturition, and
the consequent higher foetal mortality, are increased by

* H. Ellis, " Man and Woman," 1904, p. 429,


the larger size and greater weight of the male foetus com-
pared to the female.

This applies not only to the boy's head, which, as a rule,
is larger than a girl's, but usually to the whole body also,
which necessarily undergoes greater compression in its
passage through the genital canal; hence we find that the
proportion of still-born boys is very much larger than that
of still-born girls, the ratio being 138 still-born boys to 100
still-born girls. So that we have not only more living males
born than females, but also a still larger proportion of dead
full-time males to dead females. Abortions and premature
births are also more often males than females, so that male
conceptions exceed female conceptions, the ratio being about
no male conceptions to 100 female.

Even after birth there is, especially during the first year of
life, a much greater liability for the male infant to die so
much so that although, as we have seen, more boys are
born than girls, the proportions are reduced to almost even
terms by the end of the first year, owing to this greater
male mortality.

Drs. Pinard and Magnan found, from the examination
of over 52,000 confinements in the Clinique Baudelocque,
that during gestation the mortality among boys was scarcely
in excess of that of girls viz., 618 boys to 6n girls. So
that it is 'only during and after birth that more boys die,
the evident penalty of increased size and weight, and the
consequential compression.

During the first four years of life, in a gradually diminish-
ing degree, the mortality among males still exceeds that
among females; and this is the more remarkable when we
recall that the management of the two sexes does not
materially differ they are dressed practically identically,
and receive the same food.

Dr. Harry Campbell 1 states that the proportion of male
deaths to female for the first five years of life is 69-5 male to
59-7 female per thousand. He ascribes it to " an innate
tenacity of life on the part of the female." Dr. C. W.
Saleeby says it is " the inherent vitality of woman which is

1 H. Campbell, " Differences in the Nervous Organisation of Man and
Woman," 1891, pp. 123-5.


superior to man's," and this, he points out, is a provision
by Nature for the strain and risks of maternity. For
some interesting particulars of this higher male mortality
see also Havelock Ellis, " Man and Woman," chap, xvii.,
4th ed., 1904.

The environment of adult men and women differs con-
siderably; the woman's life is passed essentially within
doors, the man's is more out of doors,. and this very condi-
tion of life and work in the open is responsible for some of
the deaths to which women are not so liable.

Lads and men, both in their pleasures and in their occu-
pations, run many risks, and meet with not only fatal
accidents, but with fatal illnesses also, and thus help to
swell the adult male mortality.

One cannot, however, fail to agree with Dr. Harry Camp-
bell^ that

" The part played by an unfavourable environment in causing
the proportionately greater mortality of the male sex has been much

When, therefore, to the greater male infantile mortality
we add the greater adult male mortality, it becomes
abundantly evident that it was essential for Nature to
produce more boys than girls to counteract the greater
male mortality.

The greater male birth-rate is, however, more than
counterbalanced by the greater male mortality, so that
among adults the number of living females exceeds the
males. In 1901 over eighteen thousand more males than
females were born in England and Wales, but over twenty
thousand fewer females than males died during the same
time. So great has become this excess of women over men
that the proportion now stands at 107 living women to
100 men, or a total majority in these islands of 1,082,000
women up to the year 1901.

Having considered the reasons why more boys should be
born than girls, it remains to see how this excess of male
births over the female is brought about.

1 H. Campbell, op. cit., p. 122.


How, then, does Nature insure the production of more
boys than girls ?

This simple-looking question has always been one of the
most difficult ones to explain by any of the theories hitherto
put forward to elucidate the cause of sex, and the means by
which this excess of male births is brought about has
evaded all theorists. It can be readily explained by the
theory I set forth.

It is solved by the evident fact that in order to produce
more males, or boys, it will first be necessary to provide
more male ova; but, as I have already shown, the male
ova come only from the right ovary, hence it is essential to
produce more right-sided than left-sided ova. This, then,
is brought about by increasing the area of the right ovary
as compared to the left, so that more ova are produced by
the larger right or male ovary than by the opposite or
smaller left ovary.

That the ovaries are not usually the same size I have
already mentioned in the chapter on their anatomy, the
right ovary being a little larger than the left.

This actual anatomical fact has been very slowly recog-
nised by British writers, for unfortunately, in discussing the
anatomy of the ovaries, they are generally spoken of in the
singular, and their respective size is not given.

That the right ovary is the larger of the two ovaries is
definitely stated by the following authors:

William Anderson 1 says, " The right (ovary) is usually
a little larger than the left."

Clarence Webster* says, " The right ovary is larger than
the left."

George A. Pier sol 3 : "The right ovary being commonly
slightly heavier and larger than the left ovary."

Parvin 4 : " The right ovary is usually somewhat larger
than the left."

1 Anderson in " Henry Morris' Treatise on Human Anatomy," 3rd ed.
1902, p. 1106.

2 C. Webster, " Diseases of Women," 1898.

3 Piersol in Norris and Dickinson, op. tit., p. 57.

* Parvin, " Science and Art of Obstetrics," 1895, 3rd ed., p. 76.


Bonamy and Beau x show in Fig. i, Plate 72, in a young
virgin woman who died in the intermenstmal period, the right
ovary considerably larger than the left.

Berry Hart 2 shows the right ovary about a third larger
than the left.

In order to further satisfy myself of the correctness of
this fact, I have inspected the specimens at the Royal
College of Surgeons Museum, and find that specimens
Nos. 293, 296, 297, in the anatomical series, and specimens
Nos. 2818, 36i9A in the physiological series, prove it
to be true; but one specimen, No. 294, of the "Uterus
and appendages from an old woman who had borne
children," shows the left ovary, a trifle only, larger than
the right.

In several autopsies I have made in general practice on
women in the reproductive period of life I have found the
right ovary larger than the left, and the increased size was
not due to the increased size of an ovary incidental to
the presence of the menstrual period, nor was it due to the
presence of a corpus luteurn of pregnancy.

Further, I have noted the relative size of the ovaries while
watching others perform such operations as hysteropexy
for conditions which <Jo not imply disease of the ovaries
themselves. These cases have also proved that the right
ovary is the larger of the two.

Granting, therefore, that the right ovary is slightly
larger than the left ovary, we can correctly attribute the
fact that more boys are born than girls to this other fact
that the area of ovarian tissue capable of producing right-
sided or male ova is greater in extent than is the left ovary,
and thus does Nature secure the production of more male
ova than female ova.

That this is the correct solution of this vexed question,
why more boys are born than girls, is confirmed by the
equally convincing fact that twin boys are similarly much
more numerous than twin girls ; for manifestly the probability
of providing two distinct ova at the same time by the right

1 Bonamy and Beau, " Anatomy of the Human Body," Paris, part iii.,
1850, Plate 72.

2 Hart, " Atlas of Female Pelvic Anatomy," 1884, Plate vi. ( iig. 4, p. 10.


ovary is much increased by enlarging the size of that right
ovary, over the ovary of the opposite or left side.

Thus Veit, 1 out of 150,000 cases of twins, found that
50,000 cases were both boys, and 46,000 cases were both girls.

Galabin, 2 besides quoting Veit's figures, also gives, from
the Guy's Hospital Maternity Charity, the percentages as
38 per cent, both boys, 28 per cent, both girls.

Porter Mathew 3 gives the percentages as 58 per cent, both
boys, 16 per cent, both girls.

Rumpe, quoted by Jewett, gives " 31 cases both boys,
1 6 both girls."

Spiegelberg, 4 too, states that twin boys occur more often,
for " two females are rarest."

Parvin 5 also says that " twin males predominate over

Garrigues G says: " The rarest combination is that of two

Jewett 7 says: "The proportion of twin males is largely
in excess."

Not only does Nature thus relatively increase the number
of male or right-sided ova she produces, but she renders their
fertilisation more probable, by so placing the right cornu of
the uterus, the right Fallopian tube, and the right ovary,
that access to them by the spermatozoa is actually easier
than to the opposite or left side. Further, the right tube
is larger than the left, so that the passage of the spermatozoa
is facilitated (see Figs. 3 and 18).

Thus Spiegelberg, 8 Play f air, Q and Parvin 10 agree that "a
slight rotation occurs by which the left side (of the uterus) is
thrown towards the front, and the right (side) backwards. " ]
Consequently the right cornu uteri, tube, and ovary lie on a

1 Veil, quoted in Lusk's " Midwifery," 1889, p. 230.

2 Galabin's " Midwifery," 1900.

3 Porter Mathew, " Clinical Observations on Two Thousand Obstetric
Cases," 1898, p. 55.

* Spiegelberg, op. cit., p. 271.

s Parvin, op. cit., p. 165.

6 Garrigues, " Science and Art of Obstetrics," 1902, p. 259.

7 Jewett, " Practice of Obstetrics," 1907, p. 316.

8 Spiegelberg, op. cit., p. 32.

9 Playfair, op. cit., p. 33. 10 Parvin, op. cit., p. 71.

11 See also Gerrish in the chapter on " Anatomy," and Tweedy and
Wrench, " Practical Midwifery," 1908, p. 248.


lower level in the pelvis than do those of the left side when
the woman is lying on her back, and thus access of semen to
the right tube is favoured. This is still further facilitated
by the fact that more women invariably sleep on the right
side than on the left so much so, that Spiegelberg even
considered the more usual right lateral posture for sleep as
responsible for the inclination of the uterus to the right side
of the body.

From inquiries I have made of many scores, of married
women especially, I found the majority do sleep on their
right side. Further, I find this habit is due to the ana-
tomical fact of the presence of the heart on the left side ; for
in lying on the left side a woman's left breast is pressed
upon the region of her heart, and its action is not only
accelerated, but it becomes very distinctly audible to her
in fact, palpitation disturbs her rest, and this she avoids
instinctively by turning on to her other side. Here the
pressure of the right breast on the chest wall has necessarily
no disturbing effect. 1 have further proved this by noting
that women with ill-developed breasts sleep on either side
at will; a woman with well-developed breasts sleeps nearly
always on her right side. Some of the semen usually enters
the womb directly during coition, it being drawn in by a
suction-like action on the part of the uterus. Were it not
so, a mercurial vaginal injection just after coitus should
invariably prevent pregnancy, which it does not. Owing,
however, to the motility of the spermatozoa, this action
of the uterus is not absolutely essential to successful fertili-

If the Fallopian tubes are to be looked upon as receptacles
for the semen (see the chapter on " Fertilisation"), it is
evident that the tube which usually lies f on a lower level
is the one into which gravity, acting soon after coitus, will
help to carry most of the semen; and the larger right will
contain more.

Although the spermatozoa are known to travel greatly
through their own motility, yet this more dependent position
of the uterine opening of the right Fallopian tube must
to some extent help to secure the entrance into the right
tube of a greater amount of semen, and thus the fertilisation


of the right-sided ova is rendered more probable. On the
other hand, women who sleep chiefly on the left side must
render the access of semen to the right Fallopian tube more
difficult, though of course, owing to the motility of the
spermatozoa, far from impossible.

This greater accessibility of the right Fallopian tube to
the semen must, of course, only rank as a contributory
reason for more boys being born than girls ; the chief reason
being, as we have seen, that more male than female ova
are produced.

The fact that the male birth-rate among Jews of all
nations is higher than the male birth-rate among Christians
Rauber gives the figures as 107-6 male Jews to 106-4 male
Christians is due entirely to religious and social reasons,
and has nothing to do with the prohibition of sexual con-
gress till a week has elapsed after the cessation of a menstrual

The Jewish religion very strongly condemns

(a) The artificial prevention of pregnancy.

(b) The procuring of abortion.

(c) The taking of drugs with the intention of inducing


We know that women more readily abort and miscarry
with male children; hence whatever prevents abortion or
miscarriage leads to an increased number of boys being born.

The Jewish women, too, are more zealously taught the
rearing of children after their birth, so that with greater
care more male infants are reared than is the case among
Christian women.

And, again, infanticide amongst the Jews is almost

The only exception to the usual greater birth-rate of
males to females of 106 to 100 is found in illegitimate

We find that the percentage of illegitimate boys born to
illegitimate girls is reduced to 103 to 100 a difference of 3
per cent. More girls are thus born relatively, not absolutely.

This birth of a greater number of illegitimate female
children applies chiefly to young women and their first


child the result of indiscriminate insemination. It is not
seen in those young women who have more than one ille-
gitimate child, neither is it found among the children born
of people " living together," but not actually legally or
clerically married.

Illegitimacy is undoubtedly the chief cause of criminal
still-birth, and most authorities put the chances of an
illegitimate child being " still-born," when compared with
the legitimate, as about 2 to i. Bertillon puts it as 193 to

As a rule in first labours, i child in n is still-born, whereas
in other labours only i in 32 is born dead.

In this connection it is curious to note that, while Bertillon
affirms that first children are more likely to be males,
Schenk states just the opposite that among the first-born
there are a greater number of females.

Two important points must be borne in mind when we
consider this greater relative birth-rate of illegitimate girls.

FIRST. We must not forget that in unmarried women
very numerous attempts to procure abortion are made, and
that women abort and miscarry with a male child more
often and more readily than with a female.

Hence, abortion being more readily induced if the embryo
be a male, it follows that if pregnancy is not thus interrupted
a female is more likely to be born.

SECONDLY. If pregnancy proceed naturally, the careless
attention at the hands of old untrained women which the
majority of these single women receive during the actual
confinement, amounting almost to criminal neglect in the
delivery of their infants, leads to the larger-headed male
child not being helped into the world as he probably would
be were his mother married. Therefore he is more likely
to be born dead, and so is not registered.

It is possible to delay the birth, or to omit to deliver or
to tie the cord quickly enough for the child to be alive
sins of omission. There are also sins of commission I need
not allude to.

On the other hand, the smaller female infant slips more
readily into the world, and hence we get a relatively larger
number of girls born illegitimately.



As the law neither required the registration of the birth
of children born dead, nor a medical certificate of the cause
of the still-birth, many so-called still-born children were not
really so, but came alive into the world, and died of neglect,
exposure, suffocation, or other illegal means.

The Registrar-General's report for 1907 shows 1 that
' In thirty years the birth-rate of illegitimates has declined
from 14-4 per 1,000 unmarried or widowed females of pro-
creative age in 1878, to 7-8 per 1,000 in 1907."

If full details and statistics of the sex of illegitimate
conceptions, not live births only, could be procured, it is
very doubtful if they would show this greater proportion
of females.

1 Cf. " The Hospital," April 24, 1909, p. 92.



IT is difficult to trace back to its origin the belief in the
influence of lateral decumbency on sex determination.

The theories which have been advanced as to the influence
of a lateral posture on the causation of sex take three more
or less distinct forms.

The first I mention only to discredit it is that sex is
dependent on the woman lying on one side " at the time of

This contention is manifestly absurd, as a lateral position
is neither normal nor even common.

A second theory, first broached in the " Lancet," 1 was
that sex depended' on which side you habitually slept of
your wife: if on the left side, you beget girls; if on the right
side, boys are born.

In answer to this the editor of the " Lancet " asked, How
is the variation of sex in the same family to be accounted
for ? while I ask, Whence come boy and girl twins ? and
What settles the sex of the children whose fathers and mothers
did not sleep together at all ?

The third idea is of great antiquity, and has obtained wide
notoriety and belief.

It is that a woman must turn on to her right side directly
after coition for a male pregnancy to result, or on to her left
side directly after, to insure giving birth to a girl.

This theory was certainly known to Avicenna, a physician
living in Ispahan in the tenth century ; and Albertus Magnus,
in 1582, knew of it and quoted it.

Millot, a French doctor, writing in 1816, also supported
the idea, and further ascribed boys to fertilisation of the

1 " Lancet," 1870, vol. i., p. 608.



ova from the right ovary, and girls to fertilised left ova;
but, unlike my theory, he ascribed to the father his share
in sex causation.

This theory of turning on to one or other side after coition,
to produce the sexed child desired, is credited in many parts


from Dickinson and Hodge.)

The figure shows the uterus lying more in the right half of the pelvis, its anterior surface facing
more to the right, and the right tube and ovary carried backwards. The back of the pelvis,
etc., has been removed.

of the country to this day, so that it may be called the
popular view. It has been advocated without in any way
being aware of or appreciating the anatomical conditions
which secure for it at least some element of truth, as well
as prospect of success; for it is only recently that the
Fallopian tube has been acknowledged to be the most usual
site of fertilisation.


I have already alluded in Chapter XV. to the fact that
the majority of women sleep on their right side, and that
to this fact of lying chiefly on the right side Spiegelberg
(cf. p. 7) credited the usual position of the uterus in the
pelvis ; for, owing to gravity, the weight of the uterus would
cause it to fall over towards the lower level of the right side.
It must not be forgotten, too, that the presence of the rectum
also helps to press the uterus more over to the right side.

Further, I have pointed out that this position of the
uterus, with its right Fallopian tube (when the woman is
lying on her back) lower in the pelvis than the left tube,
must lead to a greater amount of semen getting into the right
tube, and thus the chances of male ova being fertilised are
much increased. Now, if the woman turn on to her right
side just after coition, the chances of semen entering the
right, tube and so fertilising a right or male ovum are still
further increased, because the uterine opening of the right
tube will then be at the lowest possible level. It is doubt-
less due to this anatomical fact that the idea has had a
substratum of truth to keep it alive.

Similarly, turning on to the left side will be quite as
effectual, although the uterine opening of the left tube is
not (in the dorsal position) already on a decidedly lower
level, as is the right tube; certain it is, however, that it
will be at the lowest level when the woman turns on to her
left side.

Hence we see there is an anatomical reason for crediting
turning on the side just after coition with helping to procure
the sex required; we must not forget, however, that the
primary essential to successful fertilisation, following turning
on one or other side, is the presence in the tube of that side
of a fertilisable ovum from the corresponding ovary.

We must not overlook that, although position may lead
to one or other tube receiving most semen, yet the spermato-
zoa are able to, and do, travel very greatly in virtue of their
own motility, as is proved in cases of pregnancy without
actual penetration or vaginal insemination.

This fact of lateral inclination leading the semen to the
tube whose uterine opening is thus on the lower level is
made use of by stock-breeders, who, by placing a cow or


mare looking down, and standing with one side down a
slope, endeavour thus to direct the spermatozoa into the
" side " of the uterus which is down-hill, and so give them
the sexed foetus they require.

I have seen this followed by the desired result, though it
is of course evident that it may fail because the ovary of the
side which gives the sex desired has not ovulated ; for every-
thing points to the fact that in the monotocous animal
ovulation takes place unilaterally, and from each ovary

A Scotch stock-breeder puts the whole matter to me thus :

" It is a well-known fact that the mother carries a colt foal or a
bull calf on the right side, and a filly or heifer on the left ; so that
if a mare is covered and left standing with her right side down hill,
she will have a colt (or male) foal."

He has been successful in this way, and tells me a veteri-
nary surgeon at the West of Scotland Agricultural College
has claimed successful production of the desired sex in one
hundred consecutive cases.

This, therefore, is a practical demonstration that the
right ova are male, and by directing the spermatozoa to
the right Fallopian tube the production of a male is rendered
more probable.

Having thus seen the effects of lateral decubitus on the
determination of sex, I shall now consider the effects of
sex on lateral decubitus in the pregnant woman.

I have already shown that occasionally the placenta is
fixed quite to one or other lateral wall of the uterus, but
more usually it is situated on the anterior or posterior wall,
slightly more to that side of the mid-line which corresponds
to the ovary which produced the ovum. Borland* says:

" The point of attachment of the fecundated ovum is generally

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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 9 of 18)