Visual cues to female physical attractiveness.
Evolutionary psychology suggests that a woman's sexual attractiveness is based on cues of health and reproductive potential. In recent years, research has focused on the ratio of the width of the waist to the width of the hips (the waist-to-hip ratio (WHR). A low WHR (i.e. a curvaceous body) is believed to correspond to the optimal fat distribution for high fertility, and so this shape should be highly attractive. In this paper we present evidence that weight scaled for height (the body mass index (BMI)) is the primary determinant of sexual attractiveness rather than WHR. BMI is also strongly linked to health and reproductive potential. Furthermore, we show how covariation of apparent BMI and WHR in previous studies led to the overestimation of the importance of WHR in the perception of female attractiveness. Finally, we show how visual cues, such as the perimeter-area ratio (PAR), can provide an accurate and reliable index of an individual's BMI and could be used by an observer to differentiate between potential partners. (+info)
Marital and parental satisfaction of married physicians with children.
OBJECTIVE: To evaluate personal and professional factors associated with marital and parental satisfaction of physicians. STUDY DESIGN: Cross-sectional study. PARTICIPANTS: A survey was sent to equal numbers of licensed male and female physicians in a Southern California county. Of 964 delivered questionnaires, 656 (68%) were returned completed. Our sample includes 415 currently married physicians with children, 64% male and 36% female. MEASUREMENTS AND MAIN RESULTS: Ratings of marital and parental satisfaction were measured on a 5-point Likert scale, 5 being extremely satisfied. Prevalence of work and home life factors was also evaluated. The mean score for marital satisfaction was 3.92 (range 1.75-5.0). Approximately half of the physicians reported high levels of marital satisfaction (63% of male physicians and 45% of female physicians). The gender difference disappeared after adjusting for age differences. Two factors were associated with high marital satisfaction: a supportive spouse (odds ratio [OR] 10.37; 95% confidence interval [CI] 2.66, 40.08) and role conflict (OR 0.61; 95% CI 0.42, 0.88). The mean score for parental satisfaction was 3. 43 (range 1.0-5.0), and approximately two thirds of both male and female physicians reported at least moderate levels of parental satisfaction. The major factors associated with parental satisfaction were a supportive spouse (OR 2.24; 95% CI 1.32, 3.80), role conflict (OR 0.35; 95% CI 0.23, 0.53), salaried practice setting (OR 2.14; 95% CI 1.21, 3.81), marriage to a spouse working in a profession (OR 2.14; 95% CI 1.21, 3.81), and marriage to a spouse working as a homemaker (OR 2.33; 95% CI 1.20, 4.56). Number of hours worked was not found to be related to either satisfaction score, but rather to an intervening variable, role conflict. CONCLUSIONS: For physicians with children, our study indicates that minimizing the level of role conflict and having a supportive spouse are associated with higher levels of marital and parental satisfaction. Working in salaried positions and marriage to a spouse who is either working in a profession or who is a stay-at-home parent are also related to high parental satisfaction. (+info)
Current status of reproductive behaviour in Africa.
The current annual population growth rate of 3.2% in Africa will double the population by the year 2025. The majority of this population is below 15 years of age, and Africa concurrently also has the highest incidence of infertility in the world. Sexual behaviour, which has been poorly studied in Africa, has a direct impact on reproductive health [including fertility, infertility and sexually transmitted diseases (STDs)]. The multiple cultures and religions which characterize the African continent also affect reproductive health. Factors that have a significant effect on reproductive health in Africa include greater prevalence of extramarital/commercial sexual activity, polygamy, lower prevalence of contraceptives, reliance on traditional practices, high incidence of STDs and teenage pregnancies. High risk reproductive behaviours are predominantly displayed by adolescents, and the prevalence of STDs, including HIV (human immunodeficiency virus), is very high in this group. Pregnancy-related complications are the major cause of health-related problems in 15-19 year old girls. Maternal mortality rates in most countries remain high. Literacy rates affect these behaviours. It is apparent that changing the sexual behaviour of adolescents is one way of reversing the adverse trends, such as STD transmission, unwanted pregnancy and poor general reproductive health. (+info)
Seasonal variations in sexual activity and their implications for sexual health promotion.
Although seasonal variations in births are observed in all human populations, the links between calendar events and sexual activity have received little attention in relation to health promotion and service provision. We have plotted various relevant data--routinely collected data for births within and outside of marriage, abortions, sexually transmitted infections, human immunodeficiency virus tests and condom sales figures--by calendar period. The trends point consistently to an increase in sexual activity and unsafe sex occurring at or around the Christmas period, and a longer but less pronounced subsidiary period of increased sexual activity and unsafe sex coinciding with the summer vacation. We conclude that seasonal patterns of sexual activity have implications for provision of sexual health services and for the timing and targeting of sexual health promotional interventions. (+info)
Highlights of the sexual activity of the heterosexual population in the province of Quebec.
OBJECTIVES: To describe and quantify the level of sexual activity of the heterosexually active population of Quebec. METHODS: The data analysed included 2889 heterosexually active individuals aged 15-60 (agemed = 32) from a 1996-7 survey on the sexual lifestyles of the general population of Quebec. Various probability distributions were studied to assess their capacity to describe and quantify the lifetime and yearly numbers of sexual partners of the sampled population. To estimate the annual rates of new partner acquisition, a generalised linear model was fitted to the number of lifetime sexual partners as a function of age, years of sexual activity, and sex. RESULTS: The mean and variance of the number of lifetime sexual partners for men (mean = 11, s2 = 163) is higher than for women (mean = 6, s2 = 72). The negative binomial and lognormal probability distributions give the most adequate fit to the lifetime number of partners for both agglomerated and stratified (by sex and age) data. The estimated annual rates of new partner acquisition provide two important results for prevention: (1) the first year of sexual activity represents the highest annual rate of new partner acquisition independent of age, (2) annual rates of new partner acquisitions increase through mid-life (ages 40-50) combined with a decrease in condom use. CONCLUSION: Problems caused by the use of large categories in the estimation of mean and variance cannot totally be overcome by fitting probability distributions to the empirical data despite good fits. Furthermore, we believe that adequate estimates of the annual rate of new partner acquisition should be a better measure of the risk of HIV infection than the number of partners since the first is a measure of incidence while the second is a measure of prevalence. (+info)
Abortion rates reflect the optimization of parental investment strategies.
Parental investment decisions in human beings, including infanticide, have usually been considered in relation to the postnatal survival probabilities of their children. A number of factors which influence parental ability and willingness to invest in offspring have been identified from these studies. Here we argue that at least some of the same factors which influence investment decisions postpartum also affect the decision to terminate a current pregnancy through voluntary abortion. We show that both female age and marital status influence the probability of abortion, with the key variable being the likelihood of future marriage. Thus, abortion procedures extend a woman's ability to manage her reproduction into the prenatal period. (+info)
Longevity and the costs of reproduction in a historical human population.
It has been argued that the priority that natural selection places on reproduction negatively affects other processes such as longevity and the problem posed by this trade-off underlies the disposable soma theory for the evolution of human ageing. Here we examine the relationship between reproduction and longevity in a historical human population (the Krummhorn, north-west Germany 1720-1870). In our initial analyses, we found no support for the hypothesized negative effects of reproduction on longevity: married women who remained childless lived no longer than women who reproduced and women who had few children lived no longer than women who had many children. However, more detailed analyses in relation to socio-economic class revealed that the extent to which reproduction has an effect on longevity is a function of the level of economic deprivation. We found that, when possible sources of confound were controlled for (e.g. duration of marriage and amount of time spent in fecund marriage), there is an increasingly strong relationship between longevity and reproduction with increasing poverty. (+info)
New estimates of intergenerational time intervals for the calculation of age and origins of mutations.
Intergenerational time intervals are frequently used in human population-genetics studies concerned with the ages and origins of mutations. In most cases, mean intervals of 20 or 25 years are used, regardless of the demographic characteristics of the population under study. Although these characteristics may vary from prehistoric to historical times, we suggest that this value is probably too low, and that the ages of some mutations may have been underestimated. Analyses were performed by using the BALSAC Population Register (Quebec, Canada), from which several intergenerational comparisons can be made. Family reconstitutions were used to measure interval lengths and variations in descending lineages. Various parameters were considered, such as spouse age at marriage, parental age, and reproduction levels. Mother-child and father-child intervals were compared. Intergenerational male and female intervals were also analyzed in 100 extended ascending genealogies. Results showed that a mean value of 30 years is a better estimate of intergenerational intervals than 20 or 25 years. As marked differences between male and female interval length were observed, specific values are proposed for mtDNA, autosomal, X-chromosomal, and Y-chromosomal loci. The applicability of these results for age estimates of mutations is discussed. (+info)