In anthropology and demography, the human sex ratio is the sex ratio for Homo sapiens (i. Anthropology (/ˌænθɹəˈpɒlədʒi/ from Greek grc ἄνθρωπος anthrōpos, "human" -λογία -logia) is the study of Demography is the statistical study of all Populations. It can be a very general science that can be applied to any kind of dynamic population that is one that changes over Sex ratio is the Ratio of Males to Females in a Population. The primary sex ratio is the ratio at the time of conception secondary sex ratio is Human beings, humans or man (Origin 1590–1600 L homō man OL hemō the earthly one (see Humus e. the ratio of males to females in a population). A ratio is an expression which compares quantities relative to each other Male (♂ refers to the sex of an organism or part of an organism which produces small mobile Gametes called spermatozoa. Female (♀ is the Sex of an Organism, or a part of an organism which produces ova (egg cells In Biology a population is the collection of inter-breeding organisms of a particular Species; in Sociology Like most sexual species, the sex ratio is approximately 1:1. In humans the secondary sex ratio (i. e. at birth) is commonly assumed to be 105 boys to 100 girls (which sometimes is shortened to "a ratio of 105"). BOY is a Canadian Indie pop band The band consists of vocalist and general instrumentalist Stephen Kozmeniuk, drummer Maurie Kaufmann, A girl is any Female Human from birth through Childhood and Adolescence to attainment of Adulthood The term may also be used to mean In human societies, however, sex ratios at birth or among infants may be considerably skewed by sex-selective abortion and infanticide. Sex-selective abortion is the targeted Abortion of a Fetus based upon its Sex. More data are available for humans than for any other species, and the human sex ratio is more studied than that of any other species, but interpreting these statistics can be difficult.
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Natural ratio
The natural sex ratio at birth is estimated close to 1. 05 males/female. Due to the generally higher life expectancy of females, sex ratio tends to even out in adult population, and result in an excess of females among the elderly (e. Life expectancy is the average number of years of life remaining at a given age g. , the male to female ratio falls from 1. 05 for the group aged 15 to 65 to 0. 70 for the group over 65 in Germany, from 1. The demography of the Federal Republic of Germany is monitored by the "Statistisches Bundesamt" ( Federal Statistical Office of Germany) 00 to 0. 72 in the USA, from 1. The United States is an urbanized nation with 808 percent of its population of 305186613 residing in cities and suburbs as of mid-year 2005 06 to 0. 91 in mainland China and from 1. 07 to 1. 02 in India).
Even in the absence of sex selection practices, a range of "normal" sex ratios at birth of between 103 to 107 boys per 100 girls has been observed in different societies, and among different ethnic and racial groups within a given society[1]. Parents frequently prefer their offspring to be of a particular sex for a variety of reasons Darwin, in his The Descent of Man, and Selection in Relation to Sex, cites a sex ratio of 120 boys to 100 girls for Jewish communities in 19th century Livonia, where infanticide is not historically documented, and the means for pre-natal sex determination did not exist, though this may be apocryphal. Charles Robert Darwin (February 12 1809 &ndash April 19 1882 was an English naturalist, who realised and demonstrated that all Species of life The Descent of Man and Selection in Relation to Sex is a book on Evolutionary theory by English naturalist Charles Darwin, first Livonia (Līvõmō Latvian and Livonija Estonian: Liivimaa; Finnish: Liivinmaa; German and Swedish: Livland
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 Indians, and 107 for mothers of Chinese or Filipino ethnicity. [2] Among European countries ca. 2001, the ratios ranged between 104 in Belgium and 107 in Portugal. In the aggregated results of 56 Demographic and Health Surveys[3] in African countries, the ratio is 103, though there is also considerable country-to-country variation. [4]
Factors affecting sex ratio in humans
Fisher's principle
Environmental
Higher incidence of Hepatitis B virus in populations is believed to increase the sex ratio while some unexplained environmental health hazards are thought to have the opposite effect. Fisher's principle explains why the Sex ratio of most species is approximately 11 [5] A 2007 survey by the Arctic Monitoring and Assessment Program noted abnormally low sex ratios in Russian Arctic villages and Inuit villages in Greenland and Canada, and attributed this imbalance to high levels of endocrine disruptors in the blood of inhabitants, including PCBs and DDT. Year 2007 ( MMVII) was a Common year starting on Monday of the Gregorian calendar in the 21st century. Inuit (plural the singular Inuk, means "man" or "person" is a general term for a group of culturally similar Indigenous peoples inhabiting Greenland (Kalaallit Nunaat meaning "Land of the Greenlanders" Grønland is a self-governing Danish Province located between the Country to "Dominion of Canada" or "Canadian Federation" or anything else please read the Talk Page Endocrine disruptors (sometimes also referred to as hormonally active agents) are Exogenous substances that act like Hormones in the Endocrine system Polychlorinated biphenyls ( PCB s are a class of Organic compounds with 1 to 10 Chlorine atoms attached to Biphenyl which is a molecule composed DDT (from its trivial name D ichloro- D iphenyl- T richloroethane is one of the best known synthetic Pesticides It is a chemical with a long These chemicals are believed to have accumulated in the tissues of fish and animals that make up the bulk of these populations' diets. [6] However, as noted in the Social Factors section below, it is important to exclude alternative explanations, including social ones, when examining large human populations whose composition by ethnicity and race may be changing.
Other factors that could possibly affect the sex ratio include:
- Social status of the mother, known to be a factor in influencing the sex ratio of certain animals such as swine[7][8], but apparently not in humans [9]
- Whether the mother smokes [10]
- Miscarriages caused by maternal malnutrition, since they occur slightly more often to male foeti than to female ones [11]
- Whether the mother has a partner or other support network[12], although this correlation is widely considered the effect of an unknown third factor
- Environmental temperature during pregnancy [13]
Social
Data sources and data quality issues
Sex ratios at birth for human societies may be unusual not only because of cultural preferences and social practices that favor the birth or survival of one sex over the other (more often favoring males than favoring females) but also because of incomplete or inaccurate reporting or recording of the births or the survival of infants. Even what constitutes a live birth or infant death may vary from one society to another. A live birth occurs when a Fetus, whatever its Gestational age, exits the Maternal body and subsequently shows any sign of life such as voluntary Infant mortality is defined as the number of deaths of Infants (one year of age or younger per 1000 live births For example, for most of the 20th century in Russia (and the Soviet Union), extremely premature newborns (less than 28 weeks gestational age, or less than 1000 grams in weight, or less than 35 centimeters in length) were not counted as a live birth until they had survived 7 days; and if that infant died in those first 168 hours it would not be counted as an infant death. The Union of Soviet Socialist Republics (USSR was a constitutionally Socialist state that existed in Eurasia from 1922 to 1991 Such a practice led to serious underestimation of the Infant mortality rate (by 22 to 25 percent) relative to standards recommended by the World Health Organization. Infant mortality is defined as the number of deaths of Infants (one year of age or younger per 1000 live births [14]
When unusual sex ratios at birth (or any other age) are observed, it is important to examine misreporting, misrecording, or underregistration of births or deaths as a possible explanatory factor. Some researchers have attributed the highly masculine sex ratios observed in mainland China in the last 25 years in part to the underreporting of the births of female children after the implementation of the one-child policy, though alternative explanations are now generally more widely accepted, including above all the use of ultrasound technology and sex-selective abortion of female fetuses and, probably to a more limited degree, neglect or in some cases infanticide of females. Mainland China, Continental China, the Chinese mainland or simply the mainland, is a geopolitical term synonymous with the area that is under the jurisdiction The one-child policy is the Population control policy (or planned birth policy of the People's Republic of China (PRC Sex-selective abortion is the targeted Abortion of a Fetus based upon its Sex. Infanticide is the practice of someone intentionally causing the death of an Infant. In the case of China, because of deficiencies in the vital statistics registration system studies of sex ratios at birth have relied either on special fertility surveys, whose accuracy depends on whether the respondents fully report the births and survival of both male and female infants, or on the national population census for which both birth rates and death rates are calculated from the household’s reporting of births and deaths that occurred in the 18 months preceding the census. Vital statistics are the information maintained by a Government, recording the birth and Death of individuals within that government's Jurisdiction A census is the procedure of acquiring information about every member of a given population [15] To the extent that household underreporting of births or deaths is sex-selective, both fertility surveys and censuses may inaccurately reflect the actual sex ratios at birth. [16]
Illustrations of social factors at work
Sex-selective abortion and infanticide are thought to significantly skew the naturally occurring ratio in some populations. Sex-selective abortion is the targeted Abortion of a Fetus based upon its Sex. Infanticide is the practice of someone intentionally causing the death of an Infant. These practices are said to be based on a strong cultural preference for one sex -- typically males -- over the other. Reported sex ratios at birth -- outside the typical range of 103:100 to 107:100 -- thus call for an explanation of some kind. In other populations that have witnessed declining sex ratios, researchers have suggested that ecological factors may be at work. In all such reports, it is important to exclude plausible alternative explanations.
As an example of how the social composition of a human society may produce seemingly unusual changes in sex ratios, we can take a study in several counties of California where declining sex ratios had been observed. Smith and Von Behren observe that: "In the raw data, the male birth proportion is indeed declining. However, during this period, there were also shifts in demographics that influence the sex ratio. Controlling for birth order, parents’ age, and race/ethnicity, different trends emerged. White births (which account for over 80%) continued to show a statistically significant decline, while other racial groups showed non-statistically significant declines (Japanese, Native American, other), little or no change (black), or an increase (Chinese). Finally, when the white births were divided into Hispanic and non-Hispanic (possible since 1982), it was found that both white subgroups suggest an increase in male births. " They concluded "that the decline in male births in California is largely attributable to changes in demographics. "[17]
Gender imbalance
Gender imbalance is a demographic effect that may arise either as a consequence of warfare (excess of females, notably in the wake of WWI in western Europe, and WWII, particularly in the Soviet Union) or of Sex-selective abortion and infanticide (excess of males, notably in mainland China as a result of the one-child policy, or in India), or of large-scale immigration, such as that of male labourers unable to bring their families with them (as in Qatar and other Gulf countries. Demographics or demographic data refers to selected population characteristics as used in government Marketing or opinion research or the Demographic profiles War is an international relations Dispute, characterized by organized Violence between National Military units The number of World War I casualties, both World War II was humanity's deadliest war causing tens of millions of deaths Population dynamics in the 1970s and 1980s The Crude birth rate in the USSR throughout its history had been decreasing - from 44 Sex-selective abortion is the targeted Abortion of a Fetus based upon its Sex. The demographics of the People's Republic of China are characterized by a large Population with a relatively small youth cohort, which is partially a result of the The one-child policy is the Population control policy (or planned birth policy of the People's Republic of China (PRC The Demographics of India are overall remarkably diverse India's population of approximately 1 Qatar ( قطر; ˈqɑtˁɑr local pronunciation giṭar officially the State of Qatar (Arabic دولة قطر transliterated ) Gender imbalance may result in the threat of social unrest, especially in the case of an excess of low-status young males unable to find a spouse[18], and being recruited into the service of militaristic political factions.
The Northern Mariana Islands have the highest female ratio with 0. The Northern Mariana Islands, officially the Commonwealth of the Northern Mariana Islands (CNMI is a commonwealth in Political union with the United 77 males/female. Qatar has the highest male ratio, with 1. Qatar ( قطر; ˈqɑtˁɑr local pronunciation giṭar officially the State of Qatar (Arabic دولة قطر transliterated 87 males/female. For the group aged below 15, Sierra Leone has the highest female ratio with 0. Sierra Leone, officially the Republic of Sierra Leone, is a country in West Africa. 96 males/female, and the Republic of Georgia and the People's Republic of China are tied for the highest male ratio with 1. Georgia ( საქართველო, Sakartvelo) is a Transcontinental country in the Caucasus region situated at the dividing line between Talk People's Republic of China) PEOPLE'S REPUBLIC OF CHINA ARTICLE GUIDELINES 13 males/female (according to the 2006 CIA World factbook). The World Factbook ( ISSN; also known as the CIA World Factbook) is an annual publication of the Central Intelligence Agency of the
The value for the entire world population is 1. The world population is the total number of living Humans on Earth at a given time 01 males/female, with 1. 06 at birth, still 1. 06 for those under 15, 1. 03 for those between 15 and 64, and 0. 79 for those over 65.
The "First World" G7 members all have a gender ratio in the range of 0. The term " first world " refers to countries that are capitalist, which are technologically advanced and whose The G7 (also known as the G-7 or Group of Seven) is the meeting of the Finance ministers from a group of seven industrialized nations 95–0. 98 for the total population, of 1. 05–1. 07 at birth, of 1. 05–1. 06 for the group below 15, of 1. 00–1. 04 for the group aged 15–64, and of 0. 70–0. 75 for those over 65.
Countries on the Arabian peninsula tend to have a 'natural' ratio of ca. The Arabian Peninsula (in Arabic: شبه الجزيرة العربية šibh al-jazīra al-ʻarabīya or جزيرة العرب jazīrat al-ʻarab) 1. 05 at birth but a very high ratio of males for those over 65 (Saudi Arabia 1. 13, Arab Emirates 2. 73, Qatar 2. 84), indicating either an above average mortality rate for females or a below average mortality for males, or, more likely in this case, a large population of aging male guest workers. expatriate foreign worker is a person who works in a country other than the one of which he or she is a Citizen. Conversely, countries of Eastern Europe (the Baltic states, Belarus, Ukraine, Russia) tend to have a 'normal' ratio at birth but a very low ratio of males for those over 65 (Russia 0. Eastern Europe is a general term that refers to the Geopolitical region encompassing the easternmost part of the European continent. The Baltic states (Balti riigid Baltijas valstis Baltijos valstybės or Baltic countries are three countries in Northern Europe, all members of the Belarus ( Belarusian Беларусь / Biełaruś is a Landlocked country in Eastern Europe, bordered by Russia to the north and east Ukraine (Україна Ukrayina, /ukrɑˈjinɑ/ is a country in Eastern Europe. Russia (Россия Rossiya) or the Russian Federation ( Rossiyskaya Federatsiya) is a transcontinental Country extending 46, Latvia 0. 48, Ukraine 0. 52); similarly, Armenia has a far above average male ratio at birth (1. Armenia (Հայաստան transliterated: Hayastan,) officially the Republic of Armenia (Հայաստանի Հանրապետություն Hayastani 17), and a below average male ratio above 65 (0. 67). This effect may be caused by emigration of males as well as by higher male mortality. Human migration denotes any movement by Humans from one locality to another sometimes over long distances or
List of sex ratios by country/region
See also
- Sex selection
- Sex-selective abortion and infanticide
- Demographic transition
- Youth Bulge
- XY sex-determination system
- Bride kidnapping
References
- ^ Why are More Boys than Girls Being Born?
- ^ T. The Human sex ratio is the Ratio of Males to Females in a Population. Parents frequently prefer their offspring to be of a particular sex for a variety of reasons Sex-selective abortion is the targeted Abortion of a Fetus based upon its Sex. The Demographic transition model (DTM is a model used to explain the process of shift from high Birth rates and high Death rates to low birth rates and low death rates A population pyramid, also called age-sex pyramid and age structure diagram, is a graphical illustration that shows the distribution of various age groups in a The XY sex-determination system is the Sex-determination system found in Humans most other Mammals some insects ( Drosophila) and some Bride kidnapping, also known as marriage by abduction or marriage by capture, is a form of Marriage practiced in some traditional cultures in countries J. Matthews, et al. , "Trend Analysis of the Sex Ratio at Birth in the United States," National Vital Statistics Reports 53, No. 20 (June 2005).
- ^ Demographic and Health Survey
- ^ Michel Garenne, "Sex ratios at birth in African populations: A review of survey data," Human Biology 74 (December, 2002): 889-900.
- ^ Devra L. Davis, Michelle B. Gottlieb, and Julie R. Stampnitzky. 1998. "Reduced Ratio of Male to Female Births in Several Industrial Countries: A Sentinel Health Indicator?" Journal of the American Medical Association,279 (April): 1018-1023.
- ^ Man-made chemicals blamed as many more girls than boys are born in Arctic, The Guardian, 12 Sept. 2007.
- ^ Mendl M. ; Zanella A. J. ; Broom D. M. ; Whittemore C. T. 1. 1995. "Maternal social status and birth sex ratio in domestic pigs: an analysis of mechanisms", Animal Behaviour 50, No. 5: 1361-1370.
- ^ IngentaConnect Maternal social status and birth sex ratio in domestic pigs: an a
- ^ Social status and the secondary sex ratio: new evi...[Soc Biol. 2002 Spring-Summer] - PubMed Result
- ^ Cigarette smoking and the male–female sex ratio
- ^ Is maternal malnutrition associated with a low sex ratio at birth? | Human Biology | Find Articles at BNET.com
- ^ SSRN-Partnership Status and the Human Sex Ratio at Birth by Karen Norberg
- ^ Ambient temperature predicts sex ratios and male longevity - Catalano et al., 10.1073/pnas.0710711104 - Proceedings of the National Academy of Sciences
- ^ Barbara A. Anderson and Brian D. Silver. 1986. "Infant Mortality in the Soviet Union: Regional Differences and Measurement Issues," Population and Development Review 12, No. 4: 705-737.
- ^ For example, the number of births reported to family planning and other administrative agencies has been significantly lower than the number determined in population surveys and the census. See Guangyu Zhang, "Very Low Fertility in China in the 1990s: Reality or An Illusion Arising from Birth Underreporting?," Paper presented at the annual meeting of the Population Association of America, April 2004.
- ^ For studies reveal underreporting or delayed reporting of female births in China, see M. G. Merli and A. E. Raftery, "Are births underreported in rural China? Manipulation of statistical records in response to China's population policies," Demography 37 (February 1990): 109-126; and Yong Cai and William Lavely, "China’s Missing Girls: Numerical Estimates and Effects on Population Growth," The China Review 3, No. 2 (Fall 2003): 13–29.
- ^ Daniel Smith and Julie Von Behren. 2005. "Trends in the sex ratio of California births, 1960–1996," Journal of Epidemiology and Community Health 59: 1047-1053.
- ^ Bare Branches: The Security Implications of Asia's Surplus Male Population, Valerie M. Hudson and Andrea M. den Boer (2004)
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