mandatory abortion for pregnancies exceeding the quotas stipulated by the Policy Si- mon 1988. Abortion services are provided by government health facilities, and quali-
fi ed medical personnel normally perform early abortions using vacuum aspiration. Although most abortions are performed during early pregnancy, they are permitted up
to six months of gestation Hepburn and Simon 2007. Second- trimester abortions are performed in a hospital by a physician. Abortions are free, and women undergoing the
procedure are rewarded by paid leave of up to 30 days.
8
C. Ultrasound and Prenatal Sex Selection
Prenatal sex selection is usually conducted in the form of sex- selective abortion Ed- lund 1999, which hinges crucially on access to prenatal sex determination technol-
ogies.
9
Although several reliable diagnostic procedures for fetal sex determination are available, ultrasound examination is used most frequently in China because it is
inexpensive and easily accessible.
10
Although the Chinese government originally introduced B- scan ultrasound devices for diagnostic purposes, it has become the most widely used technique for prenatal
sex identifi cation. Through B- scan, fetal sex can be determined by direct visualiza- tion of the external genitalia of the developing fetus. The accuracy of the technique
is substantially improved at 15 to 16 weeks of gestation onwards.
11
With the recent development of high- resolution ultrasound equipment, and the advent of transvaginal
sonography, a diagnosis can be made as early as 11 weeks, although it is relatively inaccurate Whitlow, Lazanakis, and Economides 1999; Efrat, Akinfenwa, and Nico-
laides 1999. Most, if not all, of the obstetric ultrasound scans in China within the study period were by transabdominal sonography, and lower- resolution equipment
hindered accurate fetal sex determination in early pregnancy. The diagnostic proce- dure in an ultrasound scan is painless and safe, with the results immediately available.
More importantly, the service is relatively inexpensive and readily affordable to the ordinary household.
By 1979, China had developed the capability to manufacture its fi rst B- scan ma- chine. A considerable quantity of imported and Chinese- manufactured ultrasound
machines was introduced in the market in the early 1980s and by 1987, the number of B- scan machines used in hospitals and clinics was estimated to exceed 13,000 units,
or roughly six machines per county. According to offi cial records, the number of im- ported ultrasound machines peaked in the late 1980s; more than 2,000 state- of- the- art
color ultrasound machines were imported in 1989 alone. It was estimated that by the early 1990s, China would have the capacity to produce over 10,000 machines annu-
ally—the equivalent of four additional machines per year for each county. By the mid- 1990s, all county hospitals and clinics, and most township clinics and family planning
8. Those who undergo abortions, with the exception of unmarried women, therefore have an incentive to report them.
9. Sex- selection methods prior to conception, such as sperm sorting, do not require induced abortions. 10. Alternative methods for prenatal sex determination include amniocentesis and chorionic villus sampling
CVS, both of which require more sophisticated skills and are much more expensive. The use of amniocen- tesis or CVS for sex determination was largely confi ned to urban areas during the 1980s Hull 1990; Oomman
and Ganatra 2002. 11. For a review of the medical literature on this subject, refer to Mielke et al. 1998.
services, were equipped with ultrasound devices that could be used for prenatal sex identifi cation Chu 2001.
Concurrent with the rapid accessibility to ultrasound technology, China witnessed an unprecedented rise in the sex ratio at birth in the 1980s Chu 2001. In 1989, hav-
ing realized the potentially disastrous consequences of the abuse of this technology, the Chinese government outlawed fetal sex determination for nonmedical purposes,
and legislated substantial penalties for physicians performing such tests. Government regulations, however, proved ineffective in practice. The misuse of ultrasound technol-
ogy was often diffi cult to police, and doctors continued to help their relatives, friends, or people who paid bribes Zeng et al. 1993. Furthermore, the problem was aggra-
vated by the incentive structure under the One Child Policy. Pressed to meet the birth- planning targets that emphasized only the number of births, local offi cials turned a
blind eye to sex- selective abortions to avoid the consequences of missing birth targets.
Evidence suggests that China’s sex ratio at birth has been changing with the prac- tice of abortion. Figure 1 shows that the national sex ratio at birth from 1978 to 1990
moves in conjunction with the abortion ratio.
12
Figure 2 plots the abortion ratio versus the sex ratio at birth, based on the data on pregnancies aggregated into pregnancy- year
× pregnancy- order cells. It demonstrates that for all fetuses conceived in the same
12. Calculations are based on data from the Chinese Children Survey conducted in June 1992. The abortion ratio is defi ned as the proportion of pregnancies ending in abortion.
Figure 1 Sex Ratio at Birth and Abortion Ratio by Year
Source: Chinese Children Survey, June 1992 Note: Sex ratio at birth is defi ned as the number of male births per 100 female births. Abortion ratio is
defi ned as the proportion of pregnancies ending in abortion.
year and of the same pregnancy order, the sex ratio of live births increases with the abortion ratio. This fi nding provides clear evidence of sex- selective abortions during
this period. Notably, the positive correlation is driven mostly by second- and higher- order pregnancies, whereas for fi rst pregnancies, both the abortion ratio and the sex
ratio at birth remain stable over the years clustered in the lower left corner of the panel.
III. Empirical Approach
