Search

I explain a biosocial model of women’s gendered behavior (behavior on which the sexes differ). This model integrates a macro sociological theory with a biological theory derived from primate behavior. The sociological model is designed to explain changes in the relationship between sex and behavior over time or between groups. The biological model is designed to explain individual within-sex variance and between-sex variance in gendered behavior in a cohort. Results from an original study are presented to demonstrate that within-sex variance in women’s gendered behavior is explained well by the primate model. I conclude that human nature is gendered. The implications of this conclusion are explored for demographic and other social science research.

The Cebu Longitudinal Health and Nutrition Survey is used to examine the roles of women’s nutrition and infant feeding in determining time from birth to menses and time from menses to conception. The analysis sample includes 2,648 Filipino women followed for 24 months postpartum. Recently devised statistical estimation techniques to control for unobserved heterogeneity and endogeneity are employed in estimating a two-state hazard model. Low body mass index and lower dietary fat intake are associated with increased duration of postpartum amenorrhea. Contraceptive use, high dietary fat consumption, higher parity, and absence of spouse predict a longer waiting time to conception once menses have returned. Simulation of the hazard model is used to examine the effects of the key nutrition and lactation factors.

A goal of publicly subsidized family planning programs in the United States is to prevent unwanted births, and the primary means being used to achieve this goal is to increase coverage with physician-administered contraception, with priority being given to persons from low-income families. We analyzed data from families living in low-income neighborhoods to determine whether that means would contribute to that goal, and if so, how much unwanted fertility might be decreased through increased coverage with physician-administered methods. The results indicate that increased coverage with those methods would decrease unwanted fertility by 80 percent (79 percent among blacks, 83 percent among whites). Increasing the ratio of sterilization to pill and IUD makes the effect of the increased coverage even more dramatic.

Recent work with samples of black and white urban American women showed a clear behavioral sequence relating age at menarche to age at first intercourse to age at first birth. This paper shows that the linking of ages at menarche, intercourse, marriage, and first birth is a pattern which occurs in very diverse cultures. We present confirmatory data from the United States, Belgium, and Pakistan, and from Malay and Chinese women in Malaysia. We interpret our findings as indicating a biological process leading to (a) social interpretations of readiness for reproduction, and (b) persisting biological differences between early and late maturing women.

Despite the widespread assumption that hormones stimulate motivation for sexual behavior in adolescence, no published empirical studies have demonstrated this link. In a cross-sectional study of 78 females in the eighth, ninth, and tenth grades in public schools, we show that hormones have effects on sexual motivation and behavior. Comparison with previous results from a parallel sample of males indicates that for both sexes these effects are primarily androgenic in origin and for the most part exert their effects directly rather than through the social interpretation of age and hormone-induced pubertal development.

This paper uses married couples’ anticipated consequences of having a (another) child to predict their reproductive intentions. Parity-specific models identify different variables as predictors of reproductive behavior at different parities but do not yield interpretable patterns of difference by parity. Parity-specific models are not significantly stronger predictors of reproductive behavior. Generally, wife-only models are distinctly superior to husband-only models. Two-sex models are usually better predictors than one-sex models but not enough better to justify the additional cost.

There are substantial differences in fecundability among nine developing countries in different parts of the world. In addition, within countries, later age at marriage has a clear, positive, nonlinear effect on fecundability. Women with higher education and those with more educated husbands have higher fecundability. Urban residents have higher fecundability than rural. The higher fecundability of more recent cohorts is the most consistent observation. Since those variables most frequently shown to have inverse relationships to fertility show direct relationships to fecundability within populations, the role offecundability as a proximate variable in models of the determinants of fertility requires further specification.

Criteria are specified for distinguishing one-decision from sequential-decision models of fertility. Sequential decisions are not demonstrated by parity-specific differences in fertility determinants. Sequential models must demonstrate the importance of unanticipated intervening events in changing fertility plans or fertility experience. They must demonstrate that the intervening events are not caused by the fertility. Two empirical tests are designed to determine which model best fits the data. One test predicts fertility plans, the other fertility events. Both tests provide some support for sequential models.

This paper evaluates the impact of federally subsidized family planning programs in the United States, from 1969 to 1974, on the reproductive behavior of ever-married women, 15–44 years old. The study began with an experimental design and the random assigment of areas to treatment and control but was completed as a multivariate analysis, treating program input as an interval-scaled independent variable. Using “before” and “after” area sample surveys and patient service data from operating programs, the demographic impact of the program was estimated. The impact detected was nonsignificant; according to our analysis, overall use of physician-administered contraception was not affected by the subsidized programs. The only program-induced change of activity related to reproduction that we recorded was increased use of subsidized services in study areas with high program input and increased use of private physician services where program input was low. These findings need to be interpreted with the caution usually exercised in evaluating imperfect field experiments.

Resumen En todas las poblaciones estudiadas se ha observado quehay una variación estacional en la tasade natalidad. Se han adelantado muchas hipótesis para explicaresiavariación, incluyendo una variación estacional en lafrecuenciadel coiio, Se sabe que ésta relación es eierta para otros primates, peroen el hombre, no se ha documentado anteriormente una variación estacional en la tasa de coiios. Este trabajo presenia datos equivalentes a más deciem años-mujer sobre tasasde coito, correspondientes a cincuenta mujeres voluntarias, de rasa blanca, en su mayor parte bien educadas, en edad pre-menopáusica, casadas y conesposo presente. Se encontró que había fluctuaciones estocionales en las tasas de coito, más 0 menos de la misma magnitudque las variaciones estacionales en las tasasde nacimientos de blancos, que se han informado para la ciudad de New York 1962–1964; para los Estados Unidos 1963; y para el quintillo socioeconómico más alto de las divisiones zensalee, Baltimore, 1952–1956. Sinembargo al desplazar las tasae de nacimientos euarienta semanas para aproximarlas a las fechas de la conzepci6n, no se pudo demostrar alguna asociación con las tasas de coiio observadas. Si el esquema presentado tiene posibilidades de generalización, las variaciones estacionales en los nacimientos no pueden ser explicadas por variaciones esiacionales en el coito

Blacks are more likely than whites to have unwanted births. A common explanation for that difference is that blacks use less effective contraceptive methods, use contraception less effectively, and use contraception less often than whites. Analysis of data from 17 cities in our family planning evaluation project suggested that, among women living in low-income neighborhoods, the black-white difference in unwanted births was not due to (1) blacks reaching desired completed parity at younger ages than whites, (2) differences in age or parity in our black and white samples, (3) black-white differences in current use of physician-administered contraception, or (4) blacks being more likely than whites to adopt physician-administered contraception after having an unwanted birth. Black-white differences which might have contributed to relatively more unwanted births among blacks were (1) blacks desired fewer children, (2) blacks were less likely than whites to use nonphysician-administered methods and more likely than whites to use no contraception, and (3) blacks had higher failure rates than whites subsequent to the adoption of physician-administered methods and when not using those methods. Comparisons are made with the 1965 and 1970 National Fertility Studies, and program implications of the findings discussed.

A comparison of the number of births in New York City nine months after the Great Blackout of 1965 with comparable periods for the previous five years shows no increase in births associated with the blackout.