Sex Ratio at Birth in India, Its Relation to Birth Order, Sex of Previous Children and Use of Indigenous Medicine
PLoS ONE | www.plosone.org June 2011 | Volume 6 | Issue 6 | e20097 http://dx.plos.org/10.1371/journal.pone.0020097.
Sex Ratio at Birth in India, Its Relation to Birth Order, Sex
of Previous Children and Use of Indigenous Medicine
Samiksha Manchanda*, Bedangshu Saikia, Neeraj Gupta, Sona Chowdhary, Jacob M. Puliyel
Department of Neonatology and Pediatrics, St Stephen Hospital, Delhi, India
Abstract
Objective: Sex-ratio at birth in families with previous girls is worse than those with a boy. Our aim was to prospectively
study in a large maternal and child unit sex-ratio against previous birth sex and use of traditional medicines for sex selection.
Main Outcome Measures: Sex-ratio among mothers in families with a previous girl and in those with a previous boy,
prevalence of indigenous medicine use and sex-ratio in those using medicines for sex selection.
Results: Overall there were 806 girls to 1000 boys. The sex-ratio was 720:1000 if there was one previous girl and 178:1000 if
there were two previous girls. In second children of families with a previous boy 1017 girls were born per 1000 boys. Sexratio
in those with one previous girl, who were taking traditional medicines for sex selection, was 928:1000.
Conclusion: Evidence from the second children clearly shows the sex-ratio is being manipulated by human interventions.
More mothers with previous girls tend to use traditional medicines for sex selection, in their subsequent pregnancies. Those
taking such medication do not seem to be helped according to expectations. They seem to rely on this method and so are
less likely use more definitive methods like sex selective abortions. This is the first such prospective investigation of sex ratio
in second children looked at against the sex of previous children. More studies are needed to confirm the findings.
Citation: Manchanda S, Saikia B, Gupta N, Chowdhary S, Puliyel JM (2011) Sex Ratio at Birth in India, Its Relation to Birth Order, Sex of Previous Children and Use
of Indigenous Medicine. PLoS ONE 6(6): e20097. doi:10.1371/journal.pone.0020097
Editor: Qamaruddin Nizami, Aga Khan University, Pakistan
Received January 13, 2011; Accepted April 22, 2011; Published June 15, 2011
Copyright: 2011 Manchanda et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits
unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Funding: The authors have no support or funding to report.
Competing Interests: The authors have declared that no competing interests exist.
* E-mail: manchandasami@yahoo.com
Introduction
According to the last census, there are only 933 women for
every 1000 men in India [1]. Gender bias favoring males is largely
responsible for this [2]. Neglect of girls and women resulting in
early death [3,4,5], female infanticide [6,7] and more recently,
antenatal sex determination and female feticide [8], all contribute
to it. Several reports suggest that sex selective abortion became
more common in the 1990s [9,10] after ultrasound machines
became available widely in the 1980s [11,12]. While the Nobel
laureate Amratya Sen believes that the pattern of gender
inequality shifted from ‘mortality inequality’ to what he calls
‘natality inequality’ due to female feticide after the facility for
antenatal sex determination became available [11,13], others
suggest that parents are not substituting pre-natal for post-natal
discrimination against girls, but combining the two strategies [14].
The relative contribution of these modes of discrimination, to the
unbalanced sex ratio in India, is still unresolved [15]. It is
important to resolve this issue so as to target remedies
appropriately, before they threaten the stability and security of
society [16].
The sex ratio in newborns as registered in the birth register
(Registration of Births and Deaths Act 1969), is an indicator of the
magnitude of the problem of female feticide as it does not include
deaths due to neglect of girl children. However infanticides, in the
first few days, are often reported as still-births [15] or not reported
at all, within the incomplete birth registration system [7]. Data on
sex ratio at birth in hospital records are therefore crucial, to
estimate the influence of female feticide on the sex ratio, and
which is not affected by other factors like infanticide and neglect of
girl children.
A study of hospital birth records over 110 years published by us
previously has showed that there was an excess of boys born, if the
previous child was a girl. If the first child was girl the sex ratio was
716 girls to 1000 boys and if the first child was boy it was 1140
girls to 1000 boys [17]. This finding apparently runs counter to the
normal tendency of biological heterogeneity which results in
families having a predilection to have children of the same sex.
Biggar et al in Denmark found the probability of having another
boy increases to 51.5, 51.6, 52.4 and 54.2 percent for families with
previous one, two, three, or four prior boys, respectively [18]. The
findings in second children in our previous study points to
antenatal interventions and suggest that sex selective abortions are
practiced quite commonly to overcompensate for the slight
penchant in families to have babies of the same sex. However,
we also found this excess of boys in families with a previous girl in
a cohort of babies born in 1970s when ultrasound machines were
uncommon and the only method of sex determination was
amniocentesis and which was not available widely [17]. The
methods used by parents to overcome the tendency to have second
children of the same sex as the first are not fully understood.
The sex of second children born to parents with a previous girl
(or boy) has not previously been studied prospectively in India, to
the best of our knowledge. This study was performed to look at the
PLoS ONE | www.plosone.org 1 June 2011 | Volume 6 | Issue 6 | e20097
sex ratio in second children depending on the sex of the first child.
By studying this prospectively and interviewing mothers it was
hoped to gain insights into the practices for sex selection that are in
vogue. A priori, it was known that because antenatal sex
determination and sex selective abortions are proscribed by law,
parents would not admit to these practices, but it was felt they
would be more forthcoming about other ‘legal’ methods like use of
traditional medicines, to promote birth of babies of the desired sex.
The study hypothesis was that families with previous girls are more
likely to use traditional medicines for sex selection and that mother
taking these medicines are more likely to have a boy child.
Methods
This prospective study was done from 19 November 2008 to 18
November 2009 in a large hospital known for its maternal and
child care services in Delhi. The hospital is century old charitable
hospital in the heart of old Delhi catering to the poor and middle
class people of the city. All mothers of live born babies delivering
in hospital were eligible for inclusion. Informed consent for
participation in the study was obtained from the mothers prior to
inclusion. The primary focus of interest was mothers delivering
their second and third babies. The sex of the child at birth, the sex
of previous children was recorded. Mothers were interviewed after
they had recovered from the strain of the delivery process – usually
12 hours after delivery. The lady researcher (SM) built up a
rapport with the mothers and enquired from her if they knew of
any methods or drugs used to get babies of a particular sex. They
were also asked if they had utilized any of these methods. The data
were recorded on an Excel spreadsheet.
Sample Size Calculation
The previous data [17] from 2005 in our hospital showed the
sex ratio was 629 girls to 1000 boys if the first child was a girl. This
gives an odd ratio of 0.49 for second child being female, if the first
is female. To detect this odds ratio, in a case control design (case is
a girl been born as a second child, control being boy born as a
second child if the first is a girl child) with 5% alpha error and 90%
power, we needed to study 182 cases and 182 controls. With 80%
power this would be 136 cases and 136 controls.
We assumed for simplicity, that the prevalence of exposure –
first child being female is 50%. As the remaining 50% first
children are presumed to be males, we would need 182+182
cases and 182+182 controls, making a total of 728 babies born
as second children, to look at significance in the two sexes
separately. About 800 babies are born as second children in our
hospital in a year, and therefore we planned to study this over a
1 year period.
Statistical Methods
Sex ratio was analyzed separately for primigravidas, and in
multigravidas according to sex of their previous babies. We looked
at the sex of the newborn against the methods they admitted to
using for having babies of any particular sex, to see if any method
influenced the sex of the baby.
95% confidence intervals (CI) for the sex ratios were calculated.
Differences in proportions of the sex ratios were estimated. To
look for proportions and their CI, and the difference in
proportions with confidence intervals, we used the software
‘Statistics with Confidence’ (www.som.soton.ac.uk).
Approval of the study protocol was obtained separately from
the Hospital Research Committee and the Hospital Research
Ethic Committee.
Results
A total of 3795 mothers delivered in the hospital that year. 48
had multiple pregnancies and were not included in the study. 2773
mother who gave birth to singleton babies, participated in the
study. In the remaining, data could not be recorded on the
account of early discharge from the hospital, before the researcher
could interview the mother. A preliminary analysis was done
looking at the sex ratio in the group that were not studied and this
was no different from the sex ratio in the children studied
(difference in proportion 0.009; 95% CI 20.015 to 0.033),
suggesting that the drop-out of 974 babies did not bias the study.
Further analysis was done on the sample of 2773 mothers who
agreed to participate in the study and who signed the consent
form.
The results are tabulated in Table 1. The sex ratio in the study
sample as a whole was 806 girls to 1000 boys. In primigravida
mothers 866 girls were born to every 1000 boys. The sex ratio was
850:1000 in mothers with one previous child. However, there were
only 255 girls to 1000 boys among mothers delivering their third
child. This was significantly different from the overall sex ratio
(difference in proportion 0.243; 95% CI 0.175 to 0.229).
When looking at the sex ratio in the second babies, taking into
account the sex of the first baby, we found that for every 1000 boys
there were only 720 girls if the first was a girl and this rose to 1017
girls if the first was a boy. The difference was statistically
significant (difference in proportion 20.086; 95% CI 20.148 to
20.022).
There were 184 mothers with two previous children, 106
mother had two previous girls, 21 had two previous boys and 57
had each one girl and one boy. If the two previous children were
girls, the sex ratio in the present pregnancy was 178 girls to 1000
boys. Those with two previous boys had a sex ratio of 615 girls for
1000 boys.
Among the 1685 primiparous mothers, only 9 (0.5%) said that
they had taken traditional medicine to help them get the baby of a
desired sex. However among 978 mothers with 1 previous child,
58 (5.9%) of the mothers had taken these medicines and 54 out of
58 were from 510 mothers with a previous girl (10.6%) and 4 were
from 486 mothers with a previous boy (0.8%). Among the 54 with
a previous girl child, who had taken medication, there were 26
girls and 28 boys making the sex ratio 928 girls to 1000 boys.
Among 184 mothers with previous two children, 106 had two
previous girls and 42 of them had taken medication (39.6%); 21
had 2 previous boys and of them 1 had taken medication (4.8%);
57 had one girl and one boy previously, and of them 3 had taken
medication (5.3%).
Discussion
Some researchers have suggested that the problem of sex
selection and the status of women can be expected to be self
correcting: as men begin to dramatically outnumber women,
women’s relative rarity will increase their value; their social status
will rise and female offspring will become more desirable [19].
However, studies of societies with high sex ratio and a high
proportion of males fail to support this prediction and there is
evidence that such societies are disproportionately violent societies
[19]. When there is a shortage of women in the marriage market
the women can ‘marry up’ inevitably leaving the least desirable
men with no marriage prospects [20]. It is a consistent finding
across cultures that an overwhelming percentage of violent crime
is perpetrated by young unmarried low status males [16]. The
need for avoiding this situation is self evident.
Sex Ratio at Birth and Its Relation to Birth Order
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We found that the overall sex ratio for deliveries at our hospital was
806 girls to 1000 boys. This is even lower than the sex ratio 865:1000
we reported from our hospital in the year 2005 [17]. We found that
the sex ratio in the second babies, if the first was a girl, was even lower
at 720. The sex ratio was 1017 girls to 1000 boys if the first was a boy.
The previous retrospective study showed a similar trend where sex
ratio was 716 (CI=672 to 762) if the first child was girl and 1140
(CI=1072 to 1212) if the first was a boy. The prospectively collected
data in this study validated the finding of previous retrospective study
and suggest that parents tend to manipulate sex of their offspring. 184
mothers had had two previous children and of these 106 had two
previous girls and 21 had two previous two boys. The remaining 57
had had one boy and one girl. Sex ratio for newborns in families with
two previous girls was as low as 178 girls to 1000 boys and this
empathically underlines the inference of human interference. There
were only 21 mothers with 2 previous boys who went on to have a
third child compared to 106 who had 2 previous girls. The fact that
there were more mothers with two previous girls than there were
mothers with two previous boys suggests a tendency among mothers
with girls to have more children in the hope of having a boy, while
mothers with boy children tend to stop having more babies. In the
natural course of events where sex ratio is not manipulated by human
intervention, if there is a preference for males, the overall sex ratio will
favor girls [18]. This is because of biological heterogeneity which
results in families tending to have children of same sex. This
phenomenon is not evidenced in India which suggests there is more
direct manipulation of the sex ratio in India.
Sex ratio in mothers with 2 previous boys was 615 compared to
1017 in those with 1 previous boy. The small sample size of
mothers with 2 previous boys can be the reason for an artifactually
low sex ratio here.
Our findings are similar to the findings of Jha et al who looked at
sex in second children in a household survey. They found the
adjusted sex ratio for the second birth when the preceding child was a
girl was 759 per 1000 males. By contrast, adjusted sex ratio for second
births if the previous child was a boy was 1102:1000 [21].
One of the objectives of our prospective study was to enquire into
themethods parents may be using to get babies of the desired sex. We
were aware that parents are unlikely to incriminate themselves by
telling the investigator about antenatal sex determination. However
the use of other methods have not been proscribed by law, so we felt it
was reasonable to enquire about them in this study. A study by
Bandyopadhyay and Singh found that up to 46% mothers use sex
selection drugs. They tested 7 samples of such medicines and found 3
contained testosterone one contained progesterone and one a natural
steroid [22]. Our study found that more parents who have girls tend
to take traditional medicine in the next pregnancy. Overall, some
0.5% mothers took such medication and this percentage increased to
10% if the first child was a girl. 40% of mothers with two girls took
such medication.
We found mothers with a previous girl child are more likely to
take indigenous medication for sex selection, than mothers with
previous a previous boy. Mothers with previous girls were also
more likely to have a boy in the next pregnancy. On the face of it
may appear that these traditional medicines help mothers to have
more boys. However the sex ratio of newborns of mothers taking
traditional medicines was 928 girls to 1000 boys. This was much
higher compared to the overall ratio of 720 girls to 1000 boys in
Table 1. Sex Ratio in different Groups.
Serial
Number (Row Number)
Groups
[Numbers Girls:Boys]
Sex Ratio (Number of
Girls To 1000 Boys)
Observed Proportion
(95% CI)
Difference in proportions
between groups (Rows) [95% CI]
1 Study
Sample
[1238:1535]
806
0.446
(CI 0.428–0.465)
Row 1:2 0.018 [CI 20.048 to 0.013]
Row 1:3 0.013 [CI 20.050 to 0.023]
2 Primiparous Mothers
[754:870] 866
0.464
(CI 0.440–0.489)
Row 2:3 0.005 [CI 20.035 to 0.044]
Row 2:6 0.261 [CI 0.191 to 0.319]*
3 One Previous
Child
[438:515]
850
0.460
(CI 0.428–0.491)
Row 3:4 0.041 [CI 20.013 to 0.094]
4 Previous
Child:
Girl
[209:290]
720
0.419
(CI 0.376–0.463)
Row 4:5 0.086 [CI 20.148 to
20.022]*
5 Previous
Child:
Boy
[229:225]
1017
0.504
(CI 0.459–0.550)
Row3:5 20.045 [CI 20.100 to 0.011]
6 Two Previous
Children
[36:141]
255
0.203
(CI 0.151–0.269)
Row 1:6 0.243 [CI 0.175 to 0.229]*
Row 3:6 0.256 [CI 0.184 to 0.318]
7 Two Previous Girls
[15:84] 178
0.152
(CI 0.094–0.235)
Row7:9 20.229 [CI 20.447 to
20.037]*
8 One Girl And Boy
Previously
[13:44]
295
0.229
(CI 0.138–0.352)
Row 7:8 20.077 [CI 20.213 to
0.046]
9 Two Previous
Boys
[8:13]
615
0.381
(CI 0.209–0.591)
Row 8:9 20.153 [CI 20.381 to
0.060]
*Statistically significant difference in proportion.
doi:10.1371/journal.pone.0020097.t001
Sex Ratio at Birth and Its Relation to Birth Order
PLoS ONE | www.plosone.org 3 June 2011 | Volume 6 | Issue 6 | e20097
mothers with one previous girl child. It was also higher than the
overall sex ratio of 806:1000. This suggests that the subset of
mother who took these medicines perhaps relied on them and it
prevented them from resorting to techniques like antenatal sex
determination and sex selective abortions.
Our study has one notable weakness. It relates to sex ratio of
children born in a hospital. According to the National Family
Health Survey 3 (2005–2006), 60% of all deliveries in India take
place at home and outside of the medical institutions. Our data
cannot therefore be said to be representative of India. It may be
argued that if the sex of the child is known antenatally, there is a
greater chance that male fetuses will be brought to the hospital for
delivery and this could alter the ratio. This may be seen as an
antenatal extension of the practice wherein boys are presented
earlier in their illness and more frequently to the hospital [4].
However the data from second children delivered at this hospital
shows that the majority of children are girls if the previous child
was a boy, and this militates against the suggestion that boy fetuses
are selectively bought to hospital for delivery.
In summary our study suggests that in spite of Pre-natal
Diagnostic Techniques (Regulation and Prevention of Misuse) Act
1994, the sex ratio at birth continues to fall. Evidence from the
second children clearly suggests this is the result of human
interventions. The use of traditional medicines in mother with
previous girl children does not influence the sex ratio and mother
who use traditional medicine perhaps do not employ other means
to manipulate the sex ratio. The exact method used by some
parents to influence the sex of their children is yet not clear. The
impulse is to blame it all on ultrasound machines but our previous
work on sex ratio in second babies has shown that the skewed sex
ratio in second children was common even in the 1970s before
ultrasound machines were freely available. More research is
needed to elucidate this.
Author Contributions
Conceived and designed the experiments: JMP SM. Performed the
experiments: SM. Analyzed the data: JMP SM. Wrote the paper: SM SC
BS NG JMP.
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