Showing papers in "Biodemography and Social Biology in 1970"

The trend of interfaith marriage in the United States

Abstract: (1970). The trend of interfaith marriage in the United States. Social Biology: Vol. 17, No. 4, pp. 253-259.

A multivariate regression analysis of differences in fertility of United States counties.

Abstract: 2 major methods have been used to study correlates of cross-sectional fertility differences: 1) the correlation of various personal characteristics with individual fertility; and 2) the correlation of average characteristics of population aggregates with the average fertility of these aggregates. In the present study 8 independent variables were correlated with 1 measure of fertility. The level of infant mortality has been shown to be associated with fertility. The universe for the present study consisted of 3134 counties (or county equivalents) in the United States. From these a 1-in-5 sample was selected by combining 2 1-in-10 systematic samples each having a different random starting point. 2 variables the proportion of Roman Catholics in the archdiocese or diocese to which the county belongs and the log 10 of the population potential in the county are found to be the most important in accounting for variation in the age-standardized fertility of United States county populations. There is little reason to doubt that these 2 variables are causally influential.

Phenotypic assortative mating among the Peruvian Cashinahua

Abstract: Among human populations, the selection of a spouse is conditioned by many factors involving not only natural but cultural determinants The social regulation of marriage, common to all human societies, narrows the range of potential spouses in a way which interferes with random mating At the genotypic level, this nonrandomness is referred to as inbreeding (Li, 1961; Wallace, 1968) and is a function of the frequency of consanguineous marriages At the phenotypic level, nonrandom mating is referred to as assortative mating (Falconer, 1961; Wallace, 1968) and is usually ascribed to the exercise of "choice" in spouse selection, though genetic relationships may be a factor as well (Crow and Felsenstein, 1968)

The probability of conception after discontinuance of oral contraception: a note on "Oral contraception coital frequency and the time required to conceive" by Westoff Bumpass and Ryder.

Abstract: Westoff Bumpass and Ryder (1969) conclude that no difference exists in the time required to conceive between women who have used oral contraception (OC) and women who have used other contraceptive methods. Yet the data on which this conclusion is based suggest a different interpretation. A table summarizes the data. Essentially the table is an extract of a life table in which only the probability of survival without becoming pregnant to the end of each ordinal month is shown. If the inversion of determining the monthly probabilities of conception among the monprgnant survivors of the preceding month is performed an intriguing and suggestive pattern emerges. Because of the progressive selecting out of women with the highest fecundability a progressive secular reduction in the proportion becoming pregnant in each successive month is expected and this is the case for women who have discontinued other forms of contraception than OC. The peak at 6 months is presumably no more than an example of round number preference. With the OC users this pattern does not emerge. A marked bimodality is present strongly suggesting that the use of OC divides women into 2 population with distinct characteristics. The characteristics of these populations must be such as to explain the very much lower conception rate of the OC users in the first 2 months. The authors explain this difference as being due in part to a higher rate of accidental pregnancy among users of less efficient methods and partly to lack of sophistication among users of other methods in interpreting the question of how long it takes to become pregnant. Neither of these explanations accounts for the finding that pregnancy appears more likely in the 3rd month than the 2nd and more likely in the 4th month than the 3rd after discontinuance of OC. It is the OC users pattern which is abnormal and unexpected so that it seems more likely that some factor is acting to depress their fecundability than the results for other users are distorted. It is assumed that there are 2 populations of OC users 1 of which (about 80% of users) is unaffected by OC use. The other population experiences a carryover of the contraceptive effect of the pill either for 2 or for 3 months after discontinuance. A table shows the monthly probabilities of conception deduced from this model and compares them with those actually found. In every month (except the 6th) the fit is so close that no more than 1 pregnancy in the study group of 110 women separates the 2 figures. It is concluded that for 20% of OC users there is a delay of either 2 or 3 months before their capacity to conceive is restored. This is most likely due to the persistence for this time of anovulatory cycles.

Interracial marriage and admixture in Hawaii

Abstract: (1970). Interracial marriage and admixture in Hawaii. Social Biology: Vol. 17, No. 4, pp. 278-291.

Abortions, chromosomal aberrations, and radiation

Abstract: (1970). Abortions, chromosomal aberrations, and radiation. Social Biology: Vol. 17, No. 2, pp. 102-106.

The fertility of sterile and subfecund women in New Orleans

Abstract: Three sterility categories are defined: 1)sterile never pregnant (SNP) 2)sterile before completing desired fertility (SB) 3)sterile after completing desired fertility (SA). Sterility and sub-fecundity can both be viewed as having either medical-physical or social origins. 2 subfecund categories are: 1)difficulty in conceiving (DC) 2)complications in delivery or in carrying to term (CDCT). 1021 people were interviewed; 2.5% of the whites and .7% of the non-whites were SNP; 10% whites and 4.2% non-whites were SB. These categories taken together indicate a strong positive relationship in each race between the proportion of sterile women and the number of years lived in a marital union. 5% of whites and 7% non-whites were classified DC and 3.3% whites and 1.4% nonwhites were CDCT. 8.3% of the whites and 8.4% of the nonwhites were classified subfecund versus 24% whites and 12% nonwhites classified sterile. The sterile and subfecund women desired 3.18 children fecund women 3.19. SBs have 1 pregnancy less (3.00) and the SAs have 1 pregnancy more than the fecund group. Of a probability sample of reproductive-age ever-married white women it is likely that one-fourth will be sterile; most of these women will have experienced substantial fertility prior to the onset of sterility. Among non-whites about one-fifth will be sterile again with substantial prior fertility.

Gene flow and structure of United States Negro populations.

Abstract: (1970). Gene flow and structure of United States Negro populations. Social Biology: Vol. 17, No. 4, pp. 316-323.