How Do Sex Ratios Become Unbalanced?
The sex ratio at birth is almost even, with about 105 boy babies born for every 100 girls. By adolescence, higher male mortality usually results in balanced populations. In theory, if everyone picked a mate at that time, everyone would be able to marry. In reality, many demographic factors contribute to unbalanced outcomes.
Fertility rates: Baby booms. The phrase marriage squeeze was coined by the American demographer Paul Glick (1988). In the early 1960s, he observed declining marriage rates among young women and realized this outcome was in part due to the interaction of two factors: the sharp increase in fertility known as the baby boom and the reality of the mating gradient. Consider the Canadian example: in 1944, the crude birth rate was 24.0 per 1,000; in 1947, it was 28.9. Twenty years later, girls born in 1947 sought grooms two to four years older than themselves, but there were not enough for a oneto-one match. Glick observed that some of young women were squeezed out of the marriage market and predicted that some would never marry.
Fertility rates: Baby busts. In the 1970s, in the developed world, the baby boom became the baby bust. In the 1990s, young men of those cohorts sought wives two to four years younger than themselves and found them in scarce supply, creating a male marriage squeeze. Stable fertility rates yield stable sex ratios among young adults; it is fluctuations in them that produce a marriage squeeze. For a marriage squeeze, the most important factor is the stage of the population in terms of the demographic transition. Other things being equal, a sharp increase in fertility or in population growth leads to a female marriage squeeze, a circumstance found throughout the developing world. A sharp decline in fertility and a declining population, lead to a male marriage squeeze, a situation now emerging in industrialized countries.
Sex differences in mortality. In the developed world, mortality rates for males are generally higher than for females. From early adulthood, the sex ratio declines with advancing age. A contributing factor is that unmarried persons have higher mortality rates than do spouses, a difference more pronounced for men than for women. Males, especially young males, are more prone than females to institutionalization, incarceration, and violent death, an outcome that in the United States has lead to a much lower sex ratio among blacks than among whites. Male mortality is also disproportionately high in times of war, an outcome reflected in sex ratios in Vietnam and Cambodia (Goodkind 1997; Huguet et al. 2000).
Natal inequality: Missing girls in Asia. In Asian countries such as China, India, Taiwan, and South Korea, there is a strong cultural preference for sons rather than daughters. Traditionally, sex ratios in such countries have been kept low by high mortality among girl babies due to neglect, abandonment, and infanticide.
Within this cultural backdrop, two other factors have been added: the concerted effort to curb population growth and the availability of sex-selection technologies, which allow female fetuses to be identified and aborted. When the total number of children is reduced, as it is with China's one-child policy, it becomes increasingly important to not waste a pregnancy on girls. Sex-selection is most often used for second and third pregnancies (Chu 2001). In the 1980s, prenatal sex selection became widespread in spite of some official policies intended to control it. By 1992 in India, China, Taiwan, and South Korea, there were 110 to 119 boy babies born for every 100 girl babies. This practice alone, apart from other variables, guarantees a shortage of brides and a surplus of grooms, in subsequent generations.
Sex differences in migration. Migrating populations consist disproportionately of young unmarried men. In Vietnam, high male mortality due to war was further exacerbated by high out-migration of young men, creating a larger female marriage squeeze for the women left behind, and a male marriage squeeze for minority men in the host country (Goodkind 1997). In the United States, sex ratios among ethnic immigrants have been high for the first generation, but subsequently declined for second and third generations (McCaa 1993).
Regional variations: Local marriage markets. Sex ratios vary not only among countries, but also from one region to another. High sex ratios occur in areas devoted to primary industries, such as Newfoundland, Maine, Montana, and Utah (Hamilton and Otterstad 1998; Hooper and England 1988). Such regions provide good employment opportunities for young men, but few jobs for young women. Sex ratios are especially low in capital cities such as Ottawa or Washington, where government bureaucracies attract many women.
The smaller the unit of analysis, the more differences in sex ratio are observed. In Los Angeles, black women living in the inner city face a much more extreme marriage squeeze than other black women. In San Francisco, where male homosexuality is not uncommon, sex ratios calculated on the basis of male/female ratios may seem high, but in terms of heterosexual marriage, the actual sex ratio is considerable lower.
- Marriage Squeeze - Demographic Consequences Of A Female Marriage Squeeze
- Marriage Squeeze - Sex Ratios: Measuring The Marriage Squeeze
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