Sex ratio is the ratio between female births and male births during a given period in a given area. The sex ratio "naturally" observed in most populations is between 900 and 1000 girls for 1000 boys. As T.E.D. indicated in a comment, the world wide sex ratio seems to be about 943.
A low sex ratio is often pointed to as a consequence of sex-selective abortion and gender-motivated infanticide that may happen for cultural or economic reasons. It has been considered a huge issue in India and China in the last decades and different programs have been developed to fight against sex-selective abortions and infanticides.
In the state of Haryana, in the north of India, the sex ratio has been measured by the Indian census and has been as low as 861 girls born for 1000 boys in 2001, and 879 in 2011.
In 2017, it has been reported that the fight against sex-selective abortions has brought great results, with the sex-ratio state-wise rising above 950 for the first time since measurement started.
However, I find the details of the figures a bit confusing:
As per district-wise data, the sex ratio at birth during March in Kaithal, Rohtak, Jhajjar, Gurugram, Bhiwani, Jind, Fatehabad, Panchkula, Rewari, Ambala, Mewat, Sonepat and Faridabad was 864, 863, 893, 893, 893, 896, 898, 912, 913, 921, 926, 939 and 947 respectively.
The ratio in Karnal, Hisar, Yamunanagar, Sirsa, Kurukshetra, Panipat, Palwal and Narnaul was 953, 972, 974, 976, 980, 993, 1.217 and 1.279 respectively, as per information provided by the state government.
It is hard for me to understand such huge differences among the different districts. Of course, the fight against female-adverse cultural bias will be more effective in some areas than others and that explains why some districts still have a sex ratio below 900, most probably due to sex-selective abortions still occurring.
However, how can Palwal and Narnaul have a sex ratio above 1200 ? If the figures are genuine, that would mean a huge male-adverse gender selection occurred, which strikes me as very implausible. Both districts have a population of around 1.000.000, hence about 20000 births a month (using India's 19.3/1000 births rate in 2016). A ratio above 1200 would then translate as about 11000 girls and 9000 boys born in each of these states, which is statistically extremely unlikely if the probability of each gender is 0.5.
The data about births per district are probably public, but I couldn't find them online. If anyone is more gifted, I'd greatly appreciate a link to births statistics in Palwal and Narnaul per gender (for 2017 or any other recent year).
Is there any rationale that can explain a sex ratio above 1200 among large populations?
Have there been any comments by programs fighting sex-selective abortions about the credibility of the official statistics?
Is there any other example of a state or a country (pop > 1.000.000) with a sex ratio above 1200?