socio-economic change The fertility rate in China continued its fall from 2.8 births per woman in 1979 (already a sharp reduction from more than five births per woman in the early 1970s) to 1.5 by the mid 1990s. Some scholars claim that this decline is similar to that observed in other places that had no one-child restrictions, such as Thailand as well as Indian states of Kerala and Tamil Nadu, a claim designed to support the argument that China's fertility might have fallen to such levels anyway without draconian fertility restrictions. According to a 2017 study in the Journal of Economic Perspectives, "the one-child policy accelerated the already-occurring drop in fertility for a few years, but in the longer term, economic development played a more fundamental role in leading to and maintaining China's low fertility level". However, a more recent study found that China's fertility decline to very low levels by the mid 1990s was far more impressive given its lower level of socio-economic development at that time; even after taking rapid economic development into account, China's fertility restrictions likely averted over 500 million births between 1970 and 2015, with the portion caused by one-child restrictions possibly totaling 400 million. Fertility restrictions also had other unintended consequences, such as a deficit of 40 million female babies. Most of this deficit was due to sex-selective abortion as well as the 1.5 child stopping rule, which required rural parents to stop childbearing if their first born was a son. Another consequence was the acceleration of the aging of China's population. Disparity in sex ratio at birth The sex ratio of a newborn infant (between male and female births) in mainland China reached 117:100, and stabilized between 2000 and 2013, about 10% higher than the baseline, which ranges between 103:100 and 107:100. It had risen from 108:100 in 1981—at the boundary of the natural baseline—to 111:100 in 1990. According to a report by the National Population and Family Planning Commission, there will be 30million more men than women in 2020, potentially leading to social instability, and courtship-motivated emigration. The number of 30 million cited for the sex disparity is, however, likely very exaggerated, as birth statistics is skewed by late registrations and unreported births: for instance, researchers found that census statistics of women in later stages of their life do not match with the birth statistics. The disparity in the gender ratio at