Fertility

About: Fertility is a research topic. Over the lifetime, 29988 publications have been published within this topic receiving 681106 citations.

Antlers honestly advertise sperm production and quality

Abstract: Evolutionary theory proposes that exaggerated male traits have evolved via sexual selection, either through female mate choice or male-male competition. While female preferences for ornamented males have been amply demonstrated in other taxa, among mammals sexual characters are commonly regarded as weapons whose main function is to enhance male competitiveness in agonistic encounters. One particularly controversial hypothesis to explain the function of male sexual characters proposes that they advertise male fertility. We test this hypothesis in red deer (Cervus elaphus), a species where sexual characters (antlers) reach an extreme degree of elaboration. We find that a global measure of relative antler size and complexity is associated with relative testes size and sperm velocity. Our results exclude the possibility that condition dependence, age or time of culling, drive these associations. Red deer antlers could signal male fertility to females, the ability to avoid sperm depletion throughout the reproductive season and/or the competitive ability of ejaculates. By contrast, male antlers could also signal to other males not only their competitive ability at the behavioural level (fighting ability) but also at the physiological level (sperm competition).

Religion and fertility in the United States: New patterns

Abstract: In the United States, the baby boom-era pattern of high Catholic and low Protestant fertility has ended Among non-Hispanic whites in the 1980s, Catholic total fertility rates (TFRs) were about one-quarter of a child lower than Protestant rates (164 vs 191) Most of the Protestant-Catholic difference is related to later and less frequent marriage among Catholics Future research on the demography of religious groups should focus on explaining the delayed marriage pattern of Catholics, the high fertility of Mormons and frequently attending Protestants, and the very low fertility of those with no religious affiliation

Family size, fertility preferences, and sex ratio in China in the era of the one child family policy: results from national family planning and reproductive health survey

Abstract: Objectives To examine the impact of the one child family policy in China on fertility, preferred family size, and sex ratio. Design Secondary analysis of data from the Chinese cross sectional national family planning and reproductive health survey, 2001. Interviews of representative sample of women aged 15-49. Results Data were obtained from 39 585 women, with a total of 73 202 pregnancies and 56 830 live births. The average fertility rate in women over 35 (n = 17 078) was 1.94 (2.1 in rural areas and 1.4 in urban areas) and for women under 35 (n = 11 543) 1.73 (1.25 and 1.79). Smaller families were associated with younger age, higher level of education, and living in an urban area. The male to female ratio was 1.15 and rose from 1.11 in 1980-9 to 1.23 for 1996-2001. Most women wanted small families: 35% preferred one child and 57% preferred two. Conclusion Since the one child family policy began, the total birth rate and preferred family size have decreased, and a gross imbalance in the sex ratio has emerged.

“The Motherhood Wage Gap for Women in the United States: The Importance of College and Fertility Delay”

Abstract: One of the stylized facts from the past 30 years has been the declining rate of first births before age 30 for all women and the increase rate of first births after age 30 among women with four-year college degrees (Steven P. Martin, Demography, 37(4), 523–533, 2000). What are some of the factors behind women’s decision to postpone their childbearing? We hypothesize that the wage difference often observed between like-educated mothers and non-mothers (Jane Waldfogel, Journal of Labor Economics, 16, 505–545, 1998a; Journal of Economic Perspectives 12(1) 137–156, 1998b) may be affected by the postponement of childbearing until after careers are fully established. Hence, we focus on college-educated women because they are typically more career-oriented than their non-college educated counterparts and also the group most often observed postponing maternity. We use individual-level data on women from the 1979 National Longitudinal Survey of Youth (NLSY79) in order to control for individual-level unobserved heterogeneity as well as human capital characteristics, such as actual work experience, in our empirical analysis. We estimate wage equations, first producing base-line results to compare to the existing literature. Then, we expand the basic wage equation model to address fundamental econometric issues and the education/fertility issue at hand. Our empirical findings are two-fold. First, we find that college-educated mothers do not experience a motherhood wage penalty at all. In fact, they enjoy a wage boost when compared to college-educated childless women. Second, fertility delay enhances this wage boost even further. Our results provide an explanation for the observed postponement of maternity for educated women. We argue that the wage boost experienced by college-educated mothers may be the result of their search for family–friendly work environments, which, in turn, yields job matches with more female-friendly firms offering greater opportunities for advancement.