We use the 2001 and 2006 Canadian Census to study sex ratios at second birth among South Asian migrants, conditional on both the spacing between the first two children and the gender of the first-born. We find that South Asian women have an abnormally high share of boys after a first-born girl. Their sex ratio at birth is particularly skewed when the time span between the first two births is short. Several mechanisms may explain this finding. Couples with strong son preferences may attempt to conceive a boy fairly soon after a girl is born Sex-selective abortion may also happen more frequently after conceptions that occur fairly close to the birth of a first girl, because couples may limit the number of repeated abortions later in the interval. Even if sex ratios decrease over time within the birth spell, they still remain somewhat higher for live births spaced three years or longer.

我们利用 2001 年和 2006 年加拿大人口普查来研究南亚移民第二胎的性别比例，条件是前两个孩子之间的间隔和第一个孩子的性别。我们发现，南亚女性在第一个孩子出生后生下男孩的比例异常高。当前两次生育之间的时间间隔很短时，他们的出生性别比尤其不平衡。有几种机制可以解释这一发现。重男轻女的夫妇可能会在女孩出生后不久就试图怀上男孩。在第一个女孩出生后受孕后，性别选择性堕胎也可能更频繁地发生，因为夫妇可能会限制重复堕胎的次数稍后在间歇期。即使性别比例在生育期内随着时间的推移而下降，但对于间隔三年或更长时间的活产来说，性别比例仍然较高。