Editing Sex-selective abortion (section)

== Human sex ratio at birth ==
{{Main|Human sex ratio}}
[[File:Abortion Laws.svg|thumb|400px|The [[human sex ratio]] at birth can vary for natural reasons as well as from sex-selective abortion. In many nations abortion is legal (see above map, dark blue).]]
Sex-selective abortion affects the [[human sex ratio]]—the relative number of males to females in a given age group.<ref name=coevolution /> Studies and reports that discuss sex-selective abortion are based on the assumption that birth sex ratio—the overall ratio of boys and girls at birth for a regional population, is an indicator of sex-selective abortion.<ref name="James_2008" /><ref name= "Junhong_2001" />

The natural human sex ratio at birth was estimated, in a 2002 study, to be close to 106 boys to 100 girls.<ref name=pmid11976243>{{cite journal | vauthors = Grech V, Savona-Ventura C, Vassallo-Agius P | title = Research pointers: Unexplained differences in sex ratios at birth in Europe and North America | journal = BMJ | volume = 324 | issue = 7344 | pages = 1010–1011 | date = April 2002 | pmid = 11976243 | pmc = 102777 | doi = 10.1136/bmj.324.7344.1010 }}</ref> Human sex ratio at birth that is significantly different from 106 is often assumed to be correlated to the prevalence and scale of sex-selective abortion. Countries considered to have significant practices of sex-selective abortion are those with birth sex ratios of 108 and above (selective abortion of females), and 102 and below (selective abortion of males).<ref name=unfpa2012 /> This assumption is controversial, and the subject of continuing scientific studies.

=== High or low human sex ratio implies sex-selective abortion ===
One school of scholars suggest that any birth sex ratio of boys to girls that is outside of the normal 105–107 range, necessarily implies sex-selective abortion. These scholars<ref>{{cite journal | vauthors = Hesketh T, Xing ZW | title = Abnormal sex ratios in human populations: causes and consequences | journal = Proceedings of the National Academy of Sciences of the United States of America | volume = 103 | issue = 36 | pages = 13271–13275 | date = September 2006 | pmid = 16938885 | pmc = 1569153 | doi = 10.1073/pnas.0602203103 | doi-access = free | bibcode = 2006PNAS..10313271H }}</ref> claim that both the sex ratio at birth and the population sex ratio are remarkably constant in human populations. Significant deviations in birth sex ratios from the normal range can only be explained by manipulation, that is sex-selective abortion.<ref name= "Klausen_2003">{{cite journal |  vauthors = Klausen S, Wink C | year = 2003 | title = Missing Women: Revisiting the Debate | doi = 10.1080/1354570022000077999 | journal = Feminist Economics | volume = 9 | issue = 2–3| pages = 263–299 | s2cid = 154492092 }}</ref>

In a widely cited article,<ref name= "Sen_1990">{{cite book | vauthors = Sen A | chapter = More than 100 million women are missing. | title = Gender and Justice | date = July 2017 | pages = 219–222 | publisher = Routledge }}</ref> [[Amartya Sen]] compared the birth sex ratio in Europe (106) and the United States (105) with those in Asia (107+) and argued that the high sex ratios in East Asia, West Asia and South Asia may be due to excessive female mortality. Sen pointed to research that had shown that if men and women receive similar nutritional and medical attention and good health care then females have better survival rates, and it is the male which is the genetically fragile sex.<ref name=kseb />

Sen estimated [[Missing women of Asia|'missing women' from extra women who would have survived in Asia]] if it had the same ratio of women to men as Europe and the United States. According to Sen, the high birth sex ratio over decades implies a female shortfall of 11% in Asia, or over 100 million women as missing from the 3 billion combined population of South Asia, West Asia, North Africa and China.

=== High or low human sex ratio may be natural ===
Other scholars question whether birth sex ratio outside 103–107 can be due to natural reasons. William James and others<ref name="James_2008">{{cite journal | vauthors = James WH | title = Evidence that mammalian sex ratios at birth are partially controlled by parental hormone levels around the time of conception | journal = The Journal of Endocrinology | volume = 198 | issue = 1 | pages = 3–15 | date = July 2008 | pmid = 18577567 | doi = 10.1677/JOE-07-0446 | doi-access = free }}</ref><ref>{{cite journal | vauthors = James WH | title = The human sex ratio. Part 1: A review of the literature | journal = Human Biology | volume = 59 | issue = 5 | pages = 721–752 | date = October 1987 | pmid = 3319883 }}</ref><ref>{{cite journal | vauthors = James WH | title = The human sex ratio. Part 2: A hypothesis and a program of research | journal = Human Biology | volume = 59 | issue = 6 | pages = 873–900 | date = December 1987 | pmid = 3327803 }}</ref><ref>{{cite journal | vauthors = Bernstein ME | title = Studies in the human sex ratio. 5. A genetic explanation of the wartime increase in the secondary sex ratio | journal = American Journal of Human Genetics | volume = 10 | issue = 1 | pages = 68–70 | date = March 1958 | pmid = 13520702 | pmc = 1931860 }}</ref><ref name = "Meslé_2007">{{cite book | vauthors = Meslé F, Vallin J, Badurashvili I | chapter = A sharp increase in sex ratio at birth in the Caucasus. Why? How? | title = Watering the Neighbour's Garden: The Growing Demographic Female Deficit in Asia | location = Paris | publisher = Committee for International Cooperation in National Research in Demography | date = 2007 | pages = 73–88 |url= http://www.cicred.org/Eng/Publications/pdf/BOOK_singapore.pdf#page=85 |access-date=December 28, 2013 |archive-date=September 17, 2018 |archive-url= https://web.archive.org/web/20180917172708/http://www.cicred.org/Eng/Publications/pdf/BOOK_singapore.pdf#page=85 |url-status=live |isbn=978-2-910053-29-1 }}</ref> suggest that conventional assumptions have been:
* there are equal numbers of X and Y chromosomes in mammalian sperms
* X and Y stand equal chance of achieving conception
* therefore equal number of male and female zygotes are formed, and that
* therefore any variation of sex ratio at birth is due to sex selection between conception and birth.

James cautions that available scientific evidence stands against the above assumptions and conclusions. He reports that there is an excess of males at birth in almost all human populations, and the natural sex ratio at birth is usually between 102 and 108. However the ratio may deviate significantly from this range for natural reasons such as early marriage and fertility, teenage mothers, average maternal age at birth, paternal age, age gap between father and mother, late births, ethnicity, social and economic stress, warfare, environmental and hormonal effects.<ref name="James_2008" /><ref>{{cite journal | vauthors = Graffelman J, Hoekstra RF | title = A statistical analysis of the effect of warfare on the human secondary sex ratio | journal = Human Biology | volume = 72 | issue = 3 | pages = 433–445 | date = June 2000 | pmid = 10885189 }}</ref> This school of scholars support their alternate hypothesis with historical data when modern sex-selection technologies were unavailable, as well as birth sex ratio in sub-regions, and various ethnic groups of developed economies.<ref name=rjhmam>{{cite journal | vauthors = Jacobsen R, Møller H, Mouritsen A | title = Natural variation in the human sex ratio | journal = Human Reproduction | volume = 14 | issue = 12 | pages = 3120–3125 | date = December 1999 | pmid = 10601107 | doi = 10.1093/humrep/14.12.3120 | doi-access = free }}</ref><ref name=tvlkjt /> They suggest that direct abortion data should be collected and studied, instead of drawing conclusions indirectly from human sex ratio at birth.

James' hypothesis is supported by historical birth sex ratio data before technologies for ultrasonographic sex-screening were discovered and commercialized in the 1960s and 1970s, as well by reverse abnormal sex ratios currently observed in Africa. Michel Garenne reports that many African nations have, over decades, witnessed birth sex ratios below 100, that is more girls are born than boys.<ref name="Garenne_2004">{{cite journal | vauthors = Garenne M | title = Sex ratios at birth in populations of Eastern and Southern Africa. | journal = Southern African Journal of Demography | date = January 2004 | volume = 9 | issue = 1 | pages = 91–96 | jstor = 20853265 }}</ref> [[Angola]], [[Botswana]] and [[Namibia]] have reported birth sex ratios between 94 and 99, which is quite different from the presumed 104 to 106 as natural human birth sex ratio.<ref name="Garenne_2004" />{{rp|95}}

[[John Graunt]] noted that in London over a 35-year period in the 17th century (1628–62),<ref>{{cite journal | vauthors = Campbell RB | title = John Graunt, John Arbuthnott, and the human sex ratio | journal = Human Biology | volume = 73 | issue = 4 | pages = 605–610 | date = August 2001 | pmid = 11512687 | doi = 10.1353/hub.2001.0048 | s2cid = 41810038 }}</ref> the birth sex ratio was 1.07; while Korea's historical records suggest a birth sex ratio of 1.13, based on 5 million births, in 1920s over a 10-year period.<ref>{{cite journal | vauthors = Ciocco A |year=1938 |title=Variation in the Sex Ratio at Birth in the United States |journal=Human Biology |volume=10 |issue=1 |pages=36–64 |url=https://www.proquest.com/openview/202c2e5a18ba5665e9705908fc815948/1 |access-date=May 11, 2022 |archive-date=June 24, 2021 |archive-url=https://web.archive.org/web/20210624081919/https://www.proquest.com/openview/202c2e5a18ba5665e9705908fc815948/1 |url-status=live }}</ref> Other historical records from Asia too support James' hypothesis. For example, Jiang et al. claim that the birth sex ratio in China was 116–121 over a 100-year period in the late 18th and early 19th centuries; in the 120–123 range in the early 20th century; falling to 112 in the 1930s.<ref>{{cite journal | vauthors = Nie JB | title = Non-medical sex-selective abortion in China: ethical and public policy issues in the context of 40 million missing females | journal = British Medical Bulletin | volume = 98 | pages = 7–20 | year = 2011 | pmid = 21596712 | doi = 10.1093/bmb/ldr015 | doi-access = free }}</ref><ref>{{cite book | vauthors = Jiang B, Li S |year=2009 |title=The Female Deficit and the Security of Society |location=Beijing |publisher=Social Sciences Academic |pages=22–26 }}</ref>

=== Data on human sex ratio at birth ===
In the United States, the sex ratios at birth over the period 1970–2002 were 105 for the white non-Hispanic population, 104 for Mexican Americans, 103 for African Americans and Native Americans, and 107 for mothers of Chinese or Filipino ethnicity.<ref name="NCHS" /><ref>{{cite web|title=UN Sex Ratio Statistics|url=https://www.un.org/esa/population/unpop.htm|publisher=United Nations Population Division|access-date=June 29, 2017|archive-date=November 13, 2018|archive-url=https://web.archive.org/web/20181113003456/http://www.un.org/esa/population/unpop.htm|url-status=live}}</ref><ref>{{cite web|title=Sex ratio at birth (per 100 female newborn)|url=http://data.un.org/Data.aspx?q=sex+ratio+birth&d=PopDiv&f=variableID%3a52|publisher=United Nations Data Division|access-date=December 28, 2013|archive-date=June 22, 2018|archive-url=https://web.archive.org/web/20180622004852/http://data.un.org/Data.aspx?q=sex+ratio+birth&d=PopDiv&f=variableID:52|url-status=live}}</ref> In the aggregated results of 56 Demographic and Health Surveys<ref>{{cite web |url=http://www.measuredhs.com/ |title=Demographic and Health Survey |access-date=December 28, 2013 |archive-date=November 14, 2016 |archive-url=https://web.archive.org/web/20161114042446/http://www.measuredhs.com/ |url-status=live | work = Measure DHS }}</ref> in African countries, the birth sex ratio was found to be 103, though there is also considerable country-to-country, and year-to-year variation.<ref name=pmid12617497>{{cite journal | vauthors = Garenne M | title = Sex ratios at birth in African populations: a review of survey data | journal = Human Biology | volume = 74 | issue = 6 | pages = 889–900 | date = December 2002 | pmid = 12617497 | doi = 10.1353/hub.2003.0003 | s2cid = 12297795 }}</ref>

In a 2005 study, U.S. Department of Health and Human Services reported sex ratio at birth in the United States from 1940 over 62 years.<ref name="NCHS">{{cite journal | vauthors = Mathews TJ, Hamilton BE | title = Trend analysis of the sex ratio at birth in the United States | journal = National Vital Statistics Reports: From the Centers for Disease Control and Prevention, National Center for Health Statistics, National Vital Statistics System | volume = 53 | issue = 20 | pages = 1–17 | date = June 2005 | pmid = 15974501 | doi = |url=https://www.cdc.gov/nchs/data/nvsr/nvsr53/nvsr53_20.pdf|publisher=U.S. Department of Health and Human Services, National Center for Health Statistics|access-date=September 11, 2017|archive-date=June 14, 2019|archive-url=https://web.archive.org/web/20190614045635/https://www.cdc.gov/nchs/data/nvsr/nvsr53/nvsr53_20.pdf|url-status=live }}</ref> This statistical evidence suggested the following: For mothers having their first baby, the total sex ratio at birth was 106 overall, with some years at 107. For mothers having babies after the first, this ratio consistently decreased with each additional baby from 106 towards 103. The age of the mother affected the ratio: the overall ratio was 105 for mothers aged 25 to 35 at the time of birth; while mothers who were below the age of 15 or above 40 had babies with a sex ratio ranging between 94 and 111, and a total sex ratio of 104. This United States study also noted that American mothers of Hawaiian, Filipino, Chinese, Cuban and Japanese ethnicity had the highest sex ratio, with years as high as 114 and average sex ratio of 107 over the 62-year study period. Outside of United States, European nations with extensive birth records, such as Finland, report similar variations in birth sex ratios over a 250-year period, that is from 1751 to 1997 AD.<ref name="tvlkjt">{{cite journal | vauthors = Vartiainen T, Kartovaara L, Tuomisto J | title = Environmental chemicals and changes in sex ratio: analysis over 250 years in finland | journal = Environmental Health Perspectives | volume = 107 | issue = 10 | pages = 813–815 | date = October 1999 | pmid = 10504147 | pmc = 1566625 | doi = 10.1289/ehp.99107813 | bibcode = 1999EnvHP.107..813V }}</ref>

Female Selective abortions in Asia are predominantly practiced in areas such as Taiwan, China, and India. The Sex ratio at birth in Asia based on worldwide data is 104 and 107 males per 100 females, which was the accepted norm before sex selective abortion was available. Unfortunately, census results from 2000 are still being reviewed and currently unavailable.<ref name="Miller_2001">{{cite journal | vauthors = Miller BD | title = Female-selective abortion in Asia: patterns, policies, and debates | journal = American Anthropologist | volume = 103 | issue = 4 | pages = 1083–95 | date = December 2001 | pmid = 12769123 | doi = 10.1525/aa.2001.103.4.1083 | jstor = 684130 }}</ref>

In 2017, according to CIA estimates,<ref name="cia.gov"/> the countries with the highest birth sex ratio were [[Liechtenstein]] (125), [[Northern Mariana Islands]] (116), [[China]] (114), [[Armenia]] (112), [[Falkland Islands]] (112), [[India]] (112), [[Grenada]] (110), [[Hong Kong]] (110), [[Vietnam]] (110), [[Albania]] (109), [[Azerbaijan]] (109), [[San Marino]] (109), [[Isle of Man]] (108), [[Kosovo]] (108) and [[Republic of Macedonia|Macedonia]] (108). Also in 2017 the lowest ratio (i.e. more girls born) was in [[Nauru]] at 83.<ref name="cia.gov"/> There were ratios of 102 and below in several countries, most of them African countries or Black/African majority population Caribbean countries: Angola, Aruba, Barbados, Bermuda, Burkina Faso, Burundi, Cabo Verde, Cameroon, Cayman Islands, Central African Republic, Chad, Comoros, Republic of the Congo, Côte d'Ivoire, Djibouti, Eritrea, Eswatini, Ethiopia, Gabon, The Gambia, Ghana, Guinea-Bissau, Haiti, Kazakhstan, Lesotho, Liberia, Madagascar, Malawi, Mali, Mauritania, Mozambique, Niger, Puerto Rico, Qatar, Senegal, Sierra Leone, Somalia, South Africa, Togo, Uganda, Zambia.<ref name="cia.gov"/>

There is controversy about the notion of the exact natural sex ratio at birth. In a study around 2002, the natural sex ratio at birth was estimated to be close to 1.06 males/female.<ref name=pmid11976243/> There is controversy whether sex ratios outside the 103-107 range are due to sex-selection, as suggested by some scholars, or due to natural causes. The claims that unbalanced sex ratios are necessary due to sex selection have been questioned by some researchers.<ref name="James_2008" /> Some researchers argue that an unbalanced sex ratio should not be automatically held as evidence of prenatal sex-selection; Michel Garenne reports that many African nations have, over decades, witnessed birth sex ratios below 100, that is more girls are born than boys.<ref name="Garenne_2004"/> Angola, Botswana and Namibia have reported birth sex ratios between 94 and 99, which is quite different than the presumed "normal" sex ratio, meaning that significantly more girls have been born in such societies.<ref name="Garenne_2004" />{{rp|95}}

In addition, in many developing countries there are problems with [[birth registration]] and data collection, which can complicate the issue.<ref name="The consequences of son preference">{{cite journal | vauthors = Hesketh T, Lu L, Xing ZW | title = The consequences of son preference and sex-selective abortion in China and other Asian countries | journal = CMAJ | volume = 183 | issue = 12 | pages = 1374–1377 | date = September 2011 | pmid = 21402684 | pmc = 3168620 | doi = 10.1503/cmaj.101368 }}</ref> With regard to the prevalence of sex selection, the media and international attention has focused mainly on a few countries, such as China, India and the [[Caucasus]], ignoring other countries with a significant sex imbalance at birth. For example, [[Liechtenstein]]'s sex ratio is far worse than that of those countries, but little has been discussed about it, and virtually no suggestions have been made that it may practice sex selection, although it is a very conservative country where [[1984 Liechtenstein women's suffrage referendum|women could not vote until 1984]].<ref>{{cite web | vauthors = Eveleth R | date = 17 September 2013 | work = Smithsonian Magazine | url= https://www.smithsonianmag.com/smart-news/liechtenstein-has-the-most-skewed-ratio-of-baby-boys-and-girls-in-the-world-right-now-8176140/ | title=Liechtenstein Has the Most Skewed Ratio of Baby Boys and Girls in the World Right Now | access-date=December 24, 2018 | archive-date=April 9, 2019 | archive-url=https://web.archive.org/web/20190409045059/https://www.smithsonianmag.com/smart-news/liechtenstein-has-the-most-skewed-ratio-of-baby-boys-and-girls-in-the-world-right-now-8176140/ | url-status=live }}</ref><ref>{{cite web | vauthors = Kircher MM | url=https://www.businessinsider.com/china-gender-ratio-disparity-isnt-words-largest-2015-10| title=The country with the highest gender disparity at birth isn't China| website=[[Business Insider]]| date=October 30, 2015| access-date=December 24, 2018| archive-date=July 24, 2019| archive-url=https://web.archive.org/web/20190724200553/https://www.businessinsider.com.au/china-gender-ratio-disparity-isnt-words-largest-2015-10| url-status=live}}</ref> At the same time, there have been accusations that the situation in some countries, such as [[Georgia (country)|Georgia]], has been exaggerated.<ref>{{cite web | url=https://eurasianet.org/georgia-data-glitch-distorts-abortion-picture | title=Georgia: Data Glitch Distorts Abortion Picture | work = Eurasianet | access-date=December 24, 2018 | archive-date=April 9, 2019 | archive-url=https://web.archive.org/web/20190409045056/https://eurasianet.org/georgia-data-glitch-distorts-abortion-picture | url-status=live }}</ref> In 2017, Georgia' sex ratio at birth was 107, according to CIA statistics.<ref>{{cite web | url=https://www.cia.gov/library/publications/the-world-factbook/fields/2018.html | title=The World Factbook | work = Central Intelligence Agency | access-date=May 17, 2016 | archive-date=October 16, 2013 | archive-url=https://web.archive.org/web/20131016065003/https://www.cia.gov/library//publications/the-world-factbook/fields/2018.html | url-status=dead }}</ref>

=== Data reliability ===
The estimates for birth sex ratios, and thus derived sex-selective abortion, are a subject of dispute as well. For example, United States' CIA projects<ref name=cia>{{cite web | url = https://www.cia.gov/library/publications/the-world-factbook/fields/2018.html | archive-url = https://web.archive.org/web/20070613003045/https://www.cia.gov/library/publications/the-world-factbook/fields/2018.html | archive-date = 13 June 2007 | title = Sex Ratio | work = The World Factbook, CIA, US Government | date = 2013 | quote = Note: Sex ratio of 1.26 is same as 126 boys per 100 girls }}</ref> the birth sex ratio for [[Switzerland]] to be 106, while the Switzerland's Federal Statistical Office that tracks actual live births of boys and girls every year, reports the latest birth sex ratio for Switzerland as 107.<ref>{{cite web | url = http://www.bfs.admin.ch/bfs/portal/en/index/themen/01/06/blank/key/02/01.html | archive-url = https://web.archive.org/web/20081118222403/http://www.bfs.admin.ch/bfs/portal/en/index/themen/01/06/blank/key/02/01.html | archive-date = 18 November 2008 | title = Births and deliveries | work = Federal Statistical Office, Switzerland | date = 2013 }}</ref> Other variations are more significant; for example, CIA projects<ref name=cia /> the birth sex ratio for [[Pakistan]] to be 105, United Nations FPA office claims<ref>{{cite web | url = https://www.unfpa.org/webdav/site/global/shared/documents/Guilmoto_Revised_presentation_Hanoi_Oct2011.pdf | title = Sex Ratios | archive-url = https://wayback.archive-it.org/all/20120604063319/https://www.unfpa.org/webdav/site/global/shared/documents/Guilmoto_Revised_presentation_Hanoi_Oct2011.pdf | archive-date=June 4, 2012 | vauthors = Guilmoto CZ | work = UNFPA | date = 2011 | page = 13 }}</ref> the birth sex ratio for Pakistan to be 110, while the government of Pakistan claims its average birth sex ratio is 111.<ref>{{cite web | url = https://www.census.gov.pk/index.php | title = Sex ratio at birth – National and Regional Census Data | archive-url = https://web.archive.org/web/20170513014654/http://www.census.gov.pk/index.php | archive-date=May 13, 2017 | work = Pakistan Census | date = 2013 }}</ref><ref>{{cite web | url = http://www.dawn.com/news/641175/gender-imbalance-pakistans-missing-women | title = Gender Imbalance: Pakistan's Missing Women | archive-url = https://web.archive.org/web/20131230232222/http://www.dawn.com/news/641175/gender-imbalance-pakistans-missing-women | archive-date = December 30, 2013 | work = Dawn | location = Pakistan | date = 2013 }}</ref><ref>{{cite news |title=Abandoned, Aborted, or Left for Dead: These Are the Vanishing Girls of Pakistan |url=https://www.theatlantic.com/international/archive/2012/06/abandoned-aborted-or-left-for-dead-these-are-the-vanishing-girls-of-pakistan/258648/ |work=The Atlantic |date=June 19, 2012 |access-date=March 11, 2017 |archive-date=January 19, 2019 |archive-url=https://web.archive.org/web/20190119174455/https://www.dawn.com/news/641175/gender-imbalance-pakistans-missing-women |url-status=live }}</ref>

The two most studied nations with high sex ratio and sex-selective abortion are China and India. The CIA estimates<ref name=cia /> a birth sex ratio of 112 for both in recent years. However, The World Bank claims the birth sex ratio for China in 2009 was 120 boys for every 100 girls;<ref>{{cite journal | vauthors = Ebenstein AY, Sharygin EJ |title=The Consequences of the 'Missing Girls' of China |journal=The World Bank Economic Review |date=2009 |volume=23 |issue=3 |pages=399–425 |doi=10.1093/wber/lhp012 |hdl=10986/4508 |url=http://documents.worldbank.org/curated/en/498661468221674913/pdf/776250JRN020090UBLIC00Missing0Girls.pdf |access-date=March 10, 2020 |archive-date=October 10, 2016 |archive-url=https://web.archive.org/web/20161010125250/http://documents.worldbank.org/curated/en/498661468221674913/pdf/776250JRN020090UBLIC00Missing0Girls.pdf |url-status=live }}</ref> while United Nations FPA estimates China's 2011 birth sex ratio to be 118.<ref name=unfpaaugust2012 />

For India, the United Nations FPA claims a birth sex ratio of 111 over 2008–10 period,<ref name=unfpaaugust2012 /> while The World Bank and India's official 2011 Census reports a birth sex ratio of 108.<ref name=teconomist /><ref>{{cite web | url = http://www.censusindia.gov.in/2011census/population_enumeration.aspx | title = India Census 2011 Provisional Report | archive-url = https://web.archive.org/web/20140208004957/http://www.censusindia.gov.in/2011census/population_enumeration.aspx | archive-date=February 8, 2014 | work = Government of India | date = 2013 }}</ref> These variations and data reliability is important as a rise from 108 to 109 for India, or 117 to 118 for China, each with large populations, represent a possible sex-selective abortion of about 100,000 girls.
[[File:國軍臺中總醫院院徽.jpg|thumb]]
Bias is due to the unreported births in hospitals which makes a slight difference on the data they report vs the census. If parents obtain sex testing before birth, and abortion was made and it was based on female fetus, it is more likely for the abortion to happen in the hospital for safety purposes and would have been reported. With no comparative data with hospitals vs nonhospital births the length of biased would be unable to determine opposed to those countries where most hospital births occur and are actually reported.<ref name="Miller_2001"/>