Sex ratio

The sex ratio is the ratio of males to females in a population. In most sexually reproducing species, the ratio tends to be 1:1. This tendency is explained by Fisher's principle.[1] For various reasons, however, many species deviate from anything like an even sex ratio, either periodically or permanently. Examples include parthenogenic species, periodically mating organisms such as aphids, some eusocial wasps such as Polistes fuscatus and Polistes exclamans, bees, ants, and termites.[2]

The human sex ratio is of particular interest to anthropologists and demographers. In human societies, however, sex ratios at birth may be considerably skewed by factors such as the age of mother at birth,[3] and by sex-selective abortion and infanticide. Exposure to pesticides and other environmental contaminants may be a significant contributing factor as well.[4] As of 2014, the global sex ratio at birth is estimated at 107 boys to 100 girls (1000 boys per 934 girls).[5]

Types

In most species, the sex ratio varies according to the age profile of the population.[6]

It is generally divided into four subdivisions:

  • primary sex ratio — ratio at fertilization
  • secondary sex ratio — ratio at birth
  • tertiary sex ratio — ratio in sexually mature organisms
    • Also called adult sex ratio and abbreviated to ASR. ASR is defined as the proportion of adults in a population that are male.[7]
    • Operational sex ratio abbreviated as OSR is the proportion of adults in the sexually active population that are males. 'OSR' has often been confused with 'ASR' although these are conceptually different.[8]
  • quaternary sex ratio — ratio in post-reproductive organisms

Measuring these requires sophisticated mathematics since they lack clear boundaries.

Sex ratio theory

The theory of sex ratio is a field of study concerned with the accurate prediction of sex ratios in all sexual species, based on a consideration of their natural history. The field continues to be heavily influenced by Eric Charnov’s 1982 book, Sex Allocation.[9] He defines five major questions, both for his book and the field in general (slightly abbreviated here):

  1. For a dioecious species, what is the equilibrium sex ratio maintained by natural selection?
  2. For a sequential hermaphrodite, what is the equilibrium sex order and time of sex change?
  3. For a simultaneous hermaphrodite, what is the equilibrium allocation of resources to male versus female function in each breeding season?
  4. Under what conditions are the various states of hermaphroditism or dioecy evolutionarily stable? When is a mixture of sexual types stable?
  5. When does selection favour the ability of an individual to alter its allocation to male versus female function, in response to particular environmental or life history situations?

Biological research mostly concerns itself with sex allocation rather than sex ratio, sex allocation denoting the allocation of energy to either sex. Common research themes are the effects of local mate and resource competition (often abbreviated LMC and LRC, respectively).

Fisher's principle

Fisher’s principle explains why for most species, the sex ratio is approximately 1:1. Bill Hamilton expounded Fisher’s argument in his 1967 paper on “Extraordinary sex ratios”[1] as follows, given the assumption of equal parental expenditure on offspring of both sexes.

  1. Suppose male births are less common than female.
  2. A newborn male then has better mating prospects than a newborn female, and therefore can expect to have more offspring.
  3. Therefore parents genetically disposed to produce males tend to have more than average numbers of grandchildren born to them.
  4. Therefore the genes for male-producing tendencies spread, and male births become more common.
  5. As the 1:1 sex ratio is approached, the advantage associated with producing males dies away.
  6. The same reasoning holds if females are substituted for males throughout. Therefore 1:1 is the equilibrium ratio.

In modern language, the 1:1 ratio is the evolutionarily stable strategy (ESS).[10] This ratio has been observed in many species, including the bee Macrotera portalis. A study performed by Danforth observed no significant difference in the number of males and females from the 1:1 sex ratio.[11]

Examples in non-human species

Environmental and individual control

Spending equal amounts of resources to produce offspring of either sex is an evolutionarily stable strategy: if the general population deviates from this equilibrium by favoring one sex, one can obtain higher reproductive success with less effort by producing more of the other. For species where the cost of successfully raising one offspring is roughly the same regardless of its sex, this translates to an approximately equal sex ratio.

Bacteria of the genus Wolbachia cause skewed sex ratios in some arthropod species as they kill males. Sex-ratio of adult populations of pelagic copepods is usually skewed towards dominance of females. However, there are differences in adult sex ratios between families: in families in which females require multiple matings to keep producing eggs, sex ratios are less biased (close to 1); in families in which females can produce eggs continuously after only one mating, sex ratios are strongly skewed towards females.[12]

Several species of reptiles have temperature-dependent sex determination, where incubation temperature of eggs determines the sex of the individual. In the American alligator, for example, females are hatched from eggs incubated between 27.7 to 30 °C (81.9 to 86.0 °F), whereas males are hatched from eggs 32.2 to 33.8 °C (90.0 to 92.8 °F). In this method, however, all eggs in a clutch (20–50) will be of the same sex. In fact, the natural sex ratio of this species is five females to one male.[13]

In birds, mothers can influence the sex of their chicks. In peafowl, maternal body condition can influence the proportion of daughters in the range from 25% to 87%.[14]

In several different groups of fish, such as wrasses, parrotfish and clownfish, dichogamy — or sequential hermaphoditism — is normal. This can cause a discrepancy in the sex ratios as well. In the bluestreak cleaner wrasse, there is only one male for every group of 6-8 females. If the male fish dies, the strongest female changes its sex to become the male for the group. All of these wrasse are born female, and only become male in this situation. Other species, like clownfish, do this in reverse, where all start out as non-reproductive males, and the largest male becomes a female, with the second-largest male maturing to become reproductive.

Domesticated animals

Traditionally, farmers have discovered that the most economically efficient community of animals will have a large number of females and a very small number of males. A herd of cows with a few bulls or a flock of hens with one rooster are the most economical sex ratios for domesticated livestock.

Dioecious plants secondary sex ratio and amount of pollen

It was found that the amount of fertilizing pollen can influence secondary sex ratio in dioecious plants. Increase in pollen amount leads to decrease in number of male plants in the progeny. This relationship was confirmed on four plant species from three families – Rumex acetosa (Polygonaceae),[15][16] Melandrium album (Cariophyllaceae),[17][18] Cannabis sativa[19] and Humulus japonicus (Cannabinaceae).[20]

Polyandrous and cooperatively breeding homeotherms

In charadriiform birds, recent research has shown clearly that polyandry and sex-role reversal (where males care and females compete for mates) as found in phalaropes, jacanas, painted snipe and a few plover species is clearly related to a strongly male-biased adult sex ratio.[21] Those species with male care and polyandry invariably have adult sex ratios with a large surplus of males,[21] which in some cases can reach as high as six males per female.[22]

Male-biased adult sex ratios have also been shown to correlate with cooperative breeding in mammals such as alpine marmots and wild canids.[23] This correlation may also apply to cooperatively breeding birds,[24] though the evidence is less clear.[21] It is known, however, that both male-biased adult sex ratios[25] and cooperative breeding tend to evolve where caring for offspring is extremely difficult due to low secondary productivity, as in Australia[26] and Southern Africa. It is also known that in cooperative breeders where both sexes are philopatric like the varied sittella,[27] adult sex ratios are equally or more male-biased than in those cooperative species, such as fairy-wrens, treecreepers and the noisy miner[28] where females always disperse.

See also

Humans:

Institutions:

Notes

  1. ^ a b Hamilton, W.D. (1967). "Extraordinary sex ratios". Science. 156 (3774): 477–488. Bibcode:1967Sci...156..477H. doi:10.1126/science.156.3774.477. PMID 6021675.
  2. ^ Kobayashi Kazuya, Hasegawa Eisuke, Yamamoto Yuuka, Kawatsu Kazutaka, Vargo Edward L., Yoshimura Jin, Matsuura Kenji (2013). "Sex ratio biases in termites provide evidence for kin selection". Nat Commun. 4: 2048. Bibcode:2013NatCo...4E2048K. doi:10.1038/ncomms3048. PMID 23807025.CS1 maint: Multiple names: authors list (link)
  3. ^ "Trend Analysis of the sex Ratio at Birth in the United States" (PDF). U.S. Department of Health and Human Services, National Center for Health Statistics.
  4. ^ Davis, Devra Lee; Gottlieb, Michelle and Stampnitzky, Julie; "Reduced Ratio of Male to Female Births in Several Industrial Countries" in Journal of the American Medical Association; April 1, 1998, volume 279(13); pp. 1018-1023
  5. ^ "CIA Fact Book". The Central Intelligence Agency of the United States.
  6. ^ Coney N.S. Mackey (1998). "The woman as final arbiter: a case for the facultative character of the human sex ratio". Journal of Sex Research. 35 (2): 169–175. doi:10.1080/00224499809551930.
  7. ^ Wilson, K. & Hardy, I.C.W. (2002) “Statistical analysis of sex ratios: an introduction”; in Hardy, Ian C.W. (editor), Sex Ratios: Concepts and Research Methods, pp. 48–92. ISBN 0521665787
  8. ^ Székely T., Weissing F. J., Komdeur J. (2014). "Adult sex ratio variation: implications for breeding system evolution". Journal of Evolutionary Biology. 27 (8): 1500–1512. doi:10.1111/jeb.12415. PMID 24848871.CS1 maint: Multiple names: authors list (link)
  9. ^ Eric L. Charnov. (1982) Sex allocation. Princeton University Press, Princeton, New Jersey. ISBN 0-691-08312-6
  10. ^ Maynard Smith, J., Price, G.R. (1973). "The logic of animal conflict". Nature. 246 (5427): 15–8. Bibcode:1973Natur.246...15S. doi:10.1038/246015a0.CS1 maint: Multiple names: authors list (link)
  11. ^ Danforth, Bryan (1991). "Female Foraging and Intranest Behavior of a Communal Bee, Perdita portalis (Hymenoptera: Andrenidae)". Annals of the Entomological Society of America. 84 (5): 537–548. doi:10.1093/aesa/84.5.537.
  12. ^ Kiørboe, T. (2006). "Sex, sex-ratios, and the dynamics of pelagic copepod populations". Oecologia. 148 (1): 40–50. Bibcode:2006Oecol.148...40K. doi:10.1007/s00442-005-0346-3. PMID 16425044.
  13. ^ Ferguson, M.W.J., Joanen, T. (April 1982). "Temperature of egg incubation determines sex in Alligator mississippiensis". Nature. 296 (5860): 850–3. Bibcode:1982Natur.296..850F. doi:10.1038/296850a0. PMID 7070524.CS1 maint: Multiple names: authors list (link)
  14. ^ Pike, T.W., Petrie, M. (October 2005). "Maternal body condition and plasma hormones affect offspring sex ration in peafowl". Animal Behaviour. 70 (4): 745–51. doi:10.1016/j.anbehav.2004.12.020. [Egg Shell Game Lay summary] Check |laysummary= value (help).CS1 maint: Multiple names: authors list (link)
  15. ^ Correns С. (1922). "Geschlechtsbestimmung und Zahlenverhaltnis der Geschlechter beim Sauerampfer (Rumex acetosa)". Biologisches Zentralblatt. 42: 465–80.
  16. ^ Rychlewski J.; Kazlmierez Z. (1975). "Sex ratio in seeds of Rumex acetosa L. as a result of sparse or abundant pollination". Acta Biol Crac Ser Bot. 18: 101–14.
  17. ^ Correns C. (1928). "Bestimmung, Vererbung und Verteilung des Geschlechter bei den hoheren Pflanzen". Handb. Vererbungswiss. 2: 1–138.
  18. ^ Mulcahy D.L. (1967). "Optimal sex ratio in Silene alba". Heredity. 22 (3): 411–423. doi:10.1038/hdy.1967.50.
  19. ^ Riede W. (1925) Beitrage zum Geschlechts- und Anpassungs-problem. "Flora" 18/19
  20. ^ Kihara H., Hirayoshi J. (1932) Die Geschlechtschromosomen von Humulus japonicus. Sieb. et. Zuce. In: 8th Congr. Jap. Ass. Adv. Sci., p. 363—367 (cit.: Plant Breeding Abstr., 1934, 5, № 3, p. 248, ref. № 768).
  21. ^ a b c Liker András; Freckleton Robert P.; Székely Tamás (2013). "The evolution of sex roles in birds is related to adult sex ratio". Nature Communications. 4: 1587. Bibcode:2013NatCo...4E1587L. doi:10.1038/ncomms2600. PMID 23481395.
  22. ^ Kosztolányi András; Barta Zoltán; Küpper Clemens; Székely Tamás (2011). "Persistence of an extreme male-biased adult sex ratio in a natural population of a polyandrous bird". Journal of Evolutionary Biology. 24 (8): 1842–1846. doi:10.1111/j.1420-9101.2011.02305.x. PMID 21749544.
  23. ^ Allainé, Dominique; Brondex, Francine; Graziani, Laurent; Coulon, Jacques and Till-Bottraud, Irène; "Male-biased sex ratio in litters of alpine marmots supports the helper repayment hypothesis"
  24. ^ Doerr Erik D.; Doerr Veronica A.J. (2006). "Comparative demography of treecreepers: evaluating hypotheses for the evolution and maintenance of cooperative breeding". Animal Behaviour. 72 (1): 147–159. doi:10.1016/j.anbehav.2005.10.017.
  25. ^ Kokko Hanna; Jennions Michael D (2008). "Parental investment, sexual selection and sex ratios". Journal of Evolutionary Biology. 21 (4): 919–948. doi:10.1111/j.1420-9101.2008.01540.x.
  26. ^ Orians Gordon H.; Milewski Antoni V. (2007). "Ecology of Australia: the effects of nutrient-poor soils and intense fires". Biological Reviews. 82 (3): 393–423. doi:10.1111/j.1469-185x.2007.00017.x. PMID 17624961.
  27. ^ Noske R.A. (1986). "Intersexual niche segregation among three bark-foraging birds of eucalypt forests". Australian Journal of Ecology. 11 (3): 255–267. doi:10.1111/j.1442-9993.1986.tb01396.x.
  28. ^ Arnold, Kathryn E.; Griffith, Simon C.; Goldizen, Anne W. (2001). "Sex-biased hatching sequences in the cooperatively breeding noisy miner". Journal of Avian Biology. 32 (3): 219–223. doi:10.1111/j.0908-8857.2001.320303.x.

References

External links

Beti Bachao, Beti Padhao Yojana

Beti Bachao, Beti Padhao (translation: Save the daughter, educate the daughter) is a campaign of the Government of India that aims to generate awareness and improve the efficiency of welfare services intended for girls. The scheme was launched with an initial funding of ₹100 crore (US$14 million). It mainly targets the clusters in Uttar Pradesh, Haryana, Uttarakhand, Punjab, Bihar and Delhi.According to census data, the child gender ratio (0–6 years) in India was 927 girls per 1,000 boys in 2001, which dropped to 918 girls for every 1,000 boys in 2011. A 2012 UNICEF report ranked India 41st among 195 countries. In the Population Census of 2011 it was revealed that the population ratio of India 2011 is 918 females per 1000 of males. The Sex Ratio 2011 shows a downward trend from the census 2001 data.

Speaking on the occasion of International Day of the Girl Child in 2014, the Prime Minister, Narendra Modi had called for the eradication of female foeticide and invited suggestions from the citizens of India via the MyGov.in portal.The Beti Bachao, Beti Padhao (BBBP) [1] scheme was launched on 22 January 2015 by Modi. It aims to address the issue of the declining child sex ratio image (CSR) and is a national initiative jointly run by the Ministry of Women and Child Development, the Ministry of Health and Family Welfare and the Ministry of Human Resource Development. It initially focused multi-sector action in 100 districts throughout the country where there was a low CSR.

On 26 August 2016, Olympics 2016 bronze medallist Sakshi Malik was made brand ambassador for BBBP.The hashtag #SelfieWithDaughter was promoted on social media in June 2015, which started when Sunil Jaglan the sarpanch of the village Bibipur, Jind in Haryana took a selfie with his daughter Nandini and posted on Facebook on 9 June 2015. The hashtag garnered worldwide fame.

Child sex ratio

In India, the Child Sex Ratio is defined as the number of females per thousand males in the age group 0–6 years in a human population. Thus it is equal to 1000 x the reciprocal of the sex ratio (ratio of males to females in a population) in the same age group, i.e. under age seven. An imbalance in this age group will extend to older age groups in future years. Currently, the ratio of males to females is generally significantly greater than 1, i.e. there are more boys than girls.

According to the decennial Indian census, the sex ratio in the 0-6 age group in India went from 104.0 males per 100 females in 1981 to 105.8 in 1991, to 107.8 in 2001, to 108.8 in 2011. The ratio is significantly higher in certain states such as Punjab and Haryana (118 and 120 respectively per 2011 census). The child sex ratio has been more prominent for males in India for quite a while, since the 1980s with thirty fewer females to males

Chirakkal, Kannur

Chirakkal is a census town in Kannur district in the state of Kerala, India. It is 7 km from Kannur town.

According to the Indian census, Chirakkal has a population of 43,290. Males constitute 48% of the population and females 52%. Chirakkal has an average literacy rate of 96.05%, higher than the state average of 94.00%; with male literacy of 97.57% and female literacy of 94.77%.

Population of Children with age of 0-6 is 4902 which is 10.75 % of total population of Chirakkal (CT). In Chirakkal Census Town, Female Sex Ratio is of 1159 against state average of 1084. Moreover Child Sex Ratio in Chirakkal is around 1032 compared to Kerala state average of 964.

Demographics of India

India is the second most populated country in the world with nearly a fifth of the world's population. According to the 2017 revision of the World Population Prospects, the population stood at 1,324,171,354.

During 1975–2010 the population doubled to 1.2 billion. The Indian population reached the billion mark in 1998. India is projected to be the world's most populous country by 2024, surpassing the population of China. It is expected to become the first political entity in history to be home to more than 1.5 billion people by 2030, and its population is set to reach 1.7 billion by 2050. Its population growth rate is 1.13%, ranking 112th in the world in 2017.India has more than 50% of its population below the age of 25 and more than 65% below the age of 35. It is expected that, in 2020, the average age of an Indian will be 29 years, compared to 37 for China and 48 for Japan; and, by 2030, India's dependency ratio should be just over 0.4.India has more than two thousand ethnic groups, and every major religion is represented, as are four major families of languages (Indo-European, Dravidian, Austroasiatic and Sino-Tibetan languages) as well as two language isolates (the Nihali language spoken in parts of Maharashtra and the Burushaski language spoken in parts of Jammu and Kashmir (Kashmir).

Further complexity is lent by the great variation that occurs across this population on social parameters such as income and education. Only the continent of Africa exceeds the linguistic, genetic and cultural diversity of the nation of India.The sex ratio is 944 females for 1000 males (2016) (940 per 1000 in 2011) This ratio has been showing an upwards trend for the last two decades after a continuous decline in the last century.

Female foeticide in India

Female foeticide in India (Hindi: भ्रूण हत्या, translit. bhrūṇ-hatyā, lit. 'foeticide') is the abortion of a female foetus outside of legal methods. The frequency of female foeticide in India is increasing day by day. The natural sex ratio is assumed to be between 103 and 107, and any number above it is considered as suggestive of female foeticide. According to the decennial Indian census, the sex ratio in the 0 to 6 age group in India has risen from 102.4 males per 100 females in 1961, to 104.2 in 1980, to 107.5 in 2001, to 108.9 in 2011.The child sex ratio is within the normal natural range in all eastern and southern states of India, but significantly higher in certain western and particularly northwestern states such as Maharashtra, Haryana, Jammu & Kashmir (118, 120 and 116, as of 2011, respectively). The western states of Maharashtra and Rajasthan 2011 census found a child sex ratio of 113, Gujarat at 112 and Uttar Pradesh at 111.The Indian census data suggests there is a positive correlation between abnormal sex ratio and better socio-economic status and literacy. This may be connected to the dowry system in India where dowry deaths occur when a girl is seen as a financial burden. Urban India has higher child sex ratio than rural India according to 1991, 2001 and 2011 Census data, implying higher prevalence of female foeticide in urban India. Similarly, child sex ratio greater than 115 boys per 100 girls is found in regions where the predominant majority is Hindu, Muslim, Sikh or Christian; furthermore "normal" child sex ratio of 104 to 106 boys per 100 girls are also found in regions where the predominant majority is Hindu, Muslim, Sikh or Christian. These data contradict any hypotheses that may suggest that sex selection is an archaic practice which takes place among uneducated, poor sections or particular religion of the Indian society.There is an ongoing debate as to whether these high sex ratios are only caused by female foeticide or some of the higher ratio is explained by natural causes. The Indian government has passed Pre-Conception and Pre-Natal Diagnostic Techniques Act (PCPNDT) in 1994 to ban and punish prenatal sex screening and female foeticide. It is currently illegal in India to determine or disclose sex of the foetus to anyone. However, there are concerns that PCPNDT Act has been poorly enforced by authorities.

Fisher's principle

Fisher's principle is an evolutionary model that explains why the sex ratio of most species that produce offspring through sexual reproduction is approximately 1:1 between males and females. A. W. F. Edwards has remarked that it is "probably the most celebrated argument in evolutionary biology".Fisher's principle was famously outlined by Ronald Fisher in his 1930 book The Genetical Theory of Natural Selection (but has been incorrectly attributed to Fisher as original). Specifically, Fisher couched his argument in terms of parental expenditure, and predicted that parental expenditure on both sexes should be equal. Sex ratios that are 1:1 are hence known as "Fisherian", and those that are not 1:1 are "non-Fisherian" or "extraordinary" and occur because they break the assumptions made in Fisher's model.

Human sex ratio

In anthropology and demography, the human sex ratio is the ratio of males to females in a population. More data is 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.

Like most sexual species, the sex ratio in humans is approximately 1:1. Due to higher female fetal mortality, the sex ratio at birth worldwide is commonly thought to be 107 boys to 100 girls, although this value is subject to debate in the scientific community, and since the late 1980s sex selective abortions of females have caused a higher than natural proportion of male births globally, mostly due to son preference in East Asia and South Asia. Girl births become more frequent closer to the Equator in absence of sex selection; the Central African Republic even has a female surplus, with 51 percent of children born there girls. The sex ratio for the entire world population is 102 males to 100 females (2017 est.). Depending upon which definition is used, between 0.1% and 1.7% of live births are intersex.Gender imbalance may arise as a consequence of various factors including natural factors, exposure to pesticides and environmental contaminants, war casualties, sex-selective abortions, infanticides, aging, and deliberate gendercide.

Human sex ratios, either at birth or in the population as a whole, are reported in any of four ways: the ratio of males to females, the ratio of females to males, the proportion of males, or the proportion of females. If there are 108,000 males and 100,000 females the ratio of males to females is 1.080 and the proportion of males is 51.9%. Scientific literature often uses the proportion of males. This article uses the ratio of males to females, unless specified otherwise.

Janjgir–Champa district

Janjgir–Champa is a district in the Indian state of Chhattisgarh and is a small developing district. The District Headquarters Janjgir of the district Janjgir–Champa is the city of Maharaja Jajawalya Dev of the Kalachuri dynasty. Earlier a part of the Bilaspur district, Jangir was carved out in 1998 to a separate district of its own, and ran to a political controversy about the name of the freshly minted district, which it carries to date as the name "Janjgir–Champa". Inhabitants are generally migrants from nearby villages.

The present collector of Janjgir-Champa is Shri S. Bharathi Dasan.

Kerura

Kerur is a City in Bagalkot district in Karnataka, which located on NH 218. It has an average elevation of 617 meters (2024 feet). Its a birthplace of Jagadish Shettar, a former Chief Minister of Karnataka.

Kerur is a Town Panchayat city in district of Bagalkot, Karnataka. The Kerur city is divided into 16 wards for which elections are held every five years. The Kerur Town Panchayat has population of 19,731 of which 9,929 are males while 9,802 are females as per report released by Census India 2011.

Population of Children with age of 0-6 is 2691 which is 13.64 % of total population of Kerur (TP). In Kerur Town Panchayat, Female Sex Ratio is of 987 against state average of 973. Moreover Child Sex Ratio in Kerur is around 922 compared with Karnataka state average of 948. Literacy rate of Kerur city is 73.36 % lower than state average of 75.36 %. In Kerur, Male literacy is around 82.30 % while female literacy rate is 64.41 %.

Kerur Town Panchayat contains over 3,665 houses to which it supplies basic amenities like water and sewerage. It is also authorized to build roads within Town Panchayat limits and impose taxes on properties coming under its jurisdiction.

List of countries by sex ratio

The human sex ratio is the number of males for each female in a population. This is a list of sex ratios by country or region.

List of states and union territories of India by sex ratio

Sex ratio is used to describe the number of females per 1000 of males. In India it is especially significant because the ratio is heavily skewed towards men. In the Population Census of 2011 it was revealed that the population ratio of India 2011 is 943

females per 1000 of males. The Sex Ratio 2011 shows an upward trend from the census 2001 data. Census 2001 revealed that there were 933 females to that of 1000 males.

The male-skew in India's sex ratio has increased significantly since the early 20th century. In 1901 there were 3.2 million fewer women than men in India, but by the 2001 Census the disparity had increased by more than a factor of 10, to 35 million. This increase has been variously attributed to female infanticide, selective abortions (aided by increasing access to prenatal sex discernment procedures), and female child neglect. It has been suggested that the motivation for this selection against female children is due to the lower status and perceived usefulness of women in India's patriarchal society.

Meerut district

Meerut district, is one of the districts of Uttar Pradesh state of India, and Meerut is the district headquarters. Meerut district is also a part of the Meerut division. The administrative head of district of Meerut is a District Magistrate while the administrative head of Meerut Division is Divisional Commissioner, an IAS officer.

Pudukkottai district

Pudukkottai District is a district of Tamil Nadu state in southern India. The city of Pudukkottai is the district headquarters. It is also known colloquially as Pudhugai. Pudukkottai district is one of the least urbanised district in Tamil Nadu.

Pudukkottai district is bounded on the northeast and east by Thanjavur District, on the southeast by the Palk Strait, on the southwest by Ramanathapuram and Sivaganga districts, and on the west and northwest by Tiruchirapalli District. As of 2011, the district had a population of 1,618,345 with a sex-ratio of 1,015 females for every 1,000 males.

The district has an area of 4,663 km² with a coastline of 42 km. The district lies between 78° 25' and 79° 15' east longitude and between 9° 50' and 10° 40' of the north latitude.

Rajivanagar

Rajivnagar is a large village located in Zawlnuam of Mamit district, Mizoram with total 708 families residing. The Rajivnagar village has population of 3530 of which 1796 are males while 1734 are females as per Population Census 2011. Rajiv nagar also known as Aamsury is an important business center for local Chakma people.

In Rajivnagar village population of children with age 0-6 is 703 which makes up 19.92 % of total population of village. Average Sex Ratio of Rajivnagar village is 965 which is lower than Mizoram state average of 976. Child Sex Ratio for the Rajivnagar as per census is 1099, higher than Mizoram average of 970.

Rajivnagar village has low literacy rate compared with Mizoram. In 2011, literacy rate of Rajivnagar village was 48.60 % compared with 91.33 % of Mizoram. In Rajivnagar Male literacy stands at 63.11 % while female literacy rate was 33.09 %.

As per constitution of India and Panchyati Raaj Act, Rajivnagar village is administrated by Sarpanch (Head of Village) who is elected representative of village.

Sex-selective abortion

Sex-selective abortion is the practice of terminating a pregnancy based upon the predicted sex of the infant. The selective abortion of female fetuses is most common where male children are valued over female children, especially in parts of East Asia and South Asia (particularly in countries such as People's Republic of China, India and Pakistan), as well as in the Caucasus, and Western Balkans.Sex selective abortion was first documented in 1975, and became commonplace by the late 1980s in South Korea and China and around the same time or slightly later in India.

Sex-selective abortion affects the human sex ratio—the relative number of males to females in a given age group, with China and India, the two most populous countries of the world, having unbalanced gender ratios. Studies and reports focusing on sex-selective abortion are predominantly statistical; they assume that birth sex ratio—the overall ratio of boys and girls at birth for a regional population, is an indicator of sex-selective abortion. This assumption has been questioned by some scholars.Scholars who support the assumption, suggest that the expected birth sex ratio range is 103 to 107 males to females at birth. 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).

Sonbhadra district

Sonbhadra or Sonebhadra is the second largest district of Uttar Pradesh, India. Sonbhadra is the only district in India which borders four states namely Madhya Pradesh, Chhattishgarh Jharkhand and Bihar. The district has an area of 6788 km² and a population of 1,862,559 (2011 census), with a population density of 270 persons per km².It lies in the extreme southeast of the state, and is bounded by Mirzapur District to the northwest, Chandauli District to the north, Kaimur and Rohtas districts of Bihar state to the northeast, Garhwa district of Jharkhand state to the east, Balrampur District of Chhattisgarh state to the south, and Singrauli district of Madhya Pradesh state to the west.

The district headquarters is in the town of Robertsganj.Sonbhadra

district is an industrial zone and it has lots of minerals like bauxite, limestone, coal, gold etc.

Sonbhadra is called as "Energy Capital of India" because there are so many power plants.

Sonbhadra lies between vindhya and Kaimur hills, and its topology and natural environment prompted First Prime minister of India Pt. Jawarharlal Nehru to refer to Sonbhadra as The Switzerland of India.

In 2017 Uttar Pradesh's chief minister Yogi Adityanath gives recognition to "Sonbhadra" as a tourist attraction hub in Purvanchal region and further promoted by Uttar Pradesh Tourism Dept.

Thanjavur district

Thanjavur District is one of the 32 districts of the state of Tamil Nadu, in southeastern India. Its headquarters is Thanjavur. The district is located in the delta of the Cauvery River and is mostly agrarian. As of 2011, Thanjavur district had a population of 2,405,890 with a sex-ratio of 1,035 females for every 1,000 males.

Tiruvarur district

Thiruvarur district (Composite Tanjore Dist) is one of the 33 districts in the Tamil Nadu state of India. The district occupies an area of 2161 km². It lies between Nagapattinam district on the east and Thanjavur District on the west, and is bounded by the Palk Strait on the south. The district headquarters is at Thiruvarur town. As of 2011, the district had a population of 1,264,277 with a sex-ratio of 1,017 females for every 1,000 males.

Virudhunagar district

Virudhunagar District is an administrative district of Tamil Nadu state in southern India. Virudhunagar is the district headquarters and the largest city in Virudhunagar district is Rajapalayam. Virudhunagar district was formed by the separation of Old Ramanathapuram District in 1987 into Ramanathapuram District, Sivagangai District and the west part as Virudhunagar District. Virudhunagar District was formerly called Karmavirer Kamarajar District. As of 2011, Virudhunagar district had a population of 2,105,930 with a sex-ratio of 1,007 females for every 1,000 males.

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