Editing Sex-selective abortion (section)

=== 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>