Differences in sex ratio. Medical search. Frequent questions

In the evolutionary biology of sexual reproduction, operational sex ratio (OSR) is the ratio of sexually competing males that are ready to mate to sexually competing females that are ready to mate, or alternatively the local ratio of fertilizable females to sexually active males at any given time. (wikipedia.org)
The theory of OSR hypothesizes that the operational sex ratio affects the mating competition of males and females in a population. (wikipedia.org)
Whether or not it is the males or females investing more care in their offspring, if they were to lose their offspring for whatever reason, this would then change the OSR to be less biased because the once occupied sex becomes available to mate again. (wikipedia.org)
Widening of the hip bones occurs as part of the female pubertal process, [7] and estrogens (the predominant sex hormones in females) cause a widening of the pelvis as a part of sexual differentiation . (wikipedia.org)
However, not all females adhere to this stereotypical pattern of secondary sex characteristics . (wikipedia.org)
The natural human sex ratio at birth slightly favors males, with about 104 to 106 males born for every 100 females. (health.mil)
The estimated odds ratio for females was about half that of males. (bmj.com)
Males and females differ in subtle ways and understanding the mechanisms behind such differences has been a major focus of both scientific inquiry and controversy throughout the decades. (jneurosci.org)
In conclusion, the current results suggest that females are more likely than males to report breathlessness and be prescribed respiratory medications independent of differences in the severity of airflow obstruction. (ersjournals.com)
The sex-ratio for males to females of liver cancer cases was 2.3 and the difference was highly significant. (academicjournals.org)
The mean age of liver cancer patients was 47.67 ± 14.20 years, and the comparison of the means of age did not display any significant difference between males and females in terms of age. (academicjournals.org)

There was a statistically significant relationship between opium use and male sex, unemployment and cigarette smoking. (who.int)
No statistically significant differences were found between viral loads in adults and pediatric patients. (cdc.gov)

To analyse the association between sickness absence and sex segregation of occupation and of work site, respectively, and to analyse work environmental factors associated with high sickness absence. (bmj.com)
Chi-squared test was used to analyse viral load according to sex and age. (scirp.org)
Our objective was to analyse contemporary sex differences over a 20-year period. (bmj.com)

Evidence for such covariation is contradictory, possibly because systematic sources of variation (e.g. sex) have been neglected. (springer.com)
Furthermore, this study found no meaningful variation in offspring sex ratio by length of submarine or military service or by rating. (health.mil)
1997 ) Epidemiological feature of first-visit outpatients in Japan: comparison with general population and variation by sex, age, and season. (bmj.com)
Demographic factors such as age, sex, and race play an important role in understanding variation in crime rates across time and place. (encyclopedia.com)

The high prevalence of suicide among the AI/AN population and the comparative differences in suicide circumstances among AI/AN decedents illustrate some of the disparities this population faces. (cdc.gov)
Sex-related differences in prevalence may be observed in some types of migraine variants. (medscape.com)
No difference in the prevalence of depression was detected between the LDS and the non-LDS women. (byu.edu)
Neither prevalence (p=0.48) nor incidence (p=0.18) sex ratios changed significantly between 1951 and 2009. (bmj.com)

The natural human sex ratio at birth (male:female) slightly favors males, and altered sex ratios might be indicative of exposure to reproductive hazards. (health.mil)
We need to understand better how the human sex ratio is biologically determined, in order to understand how our manipulations might affect it. (ox.ac.uk)

Professor David Steinsaltz of Oxford University's Department of Statistics, one of the paper's co-authors, says: 'The higher female embryo mortality during pregnancy suggests further areas of potential investigation: we know that sex ratio can be influenced by environmental pollution and by maternal stress, but little is understood about the mechanism. (ox.ac.uk)
We calculated absolute and relative mortality sex differences for all-cause and cause-specific mortality, age-adjusted and age-specific, including the following causes: circulatory, cancers, respiratory and injuries. (bmj.com)
The age-adjusted male-to-female mortality ratio dropped 41.4%, falling from 1.47 to 1.28. (bmj.com)
Conclusions The large decline in mortality sex ratios in a Canadian province with universal healthcare over two decades signals an important population shift. (bmj.com)
Absolute and relative sex-specific mortality trends were analysed by cause, age and socioeconomic status (SES) to measure the extent to which sex convergence has been taking place. (bmj.com)

Group differences were assessed using chi-squared tests and logistic regression. (cdc.gov)
0.05) were further examined using logistic regression, controlling for age and sex. (cdc.gov)
Chi-square tests and unconditional logistic regression models were used to compare the offspring sex ratio of male submariners with 2 other active duty populations and the U.S. population. (health.mil)
Odds ratios of smoking cessation for sex, age, and diagnosis were calculated by a multivariate unconditional logistic model (table). (bmj.com)

In the analysis for 644 respondents, sex and diagnosis were found to be significant factors predicting smoking cessation. (bmj.com)

Though both sexes may be competing for mates, it is important to remember that the biased OSR predicts which sex is the predominant competitor (the sex that exhibits the most competition). (wikipedia.org)

No differences were seen in the sex ratio of the exposure groups. (cdc.gov)
But the data from the Yusho and Yucheng episodes (i.e., excess PCBs and furan exposure in cooking oil) showed no effect on the sex ratio, even with very high maternal exposures [Gomez et al. (cdc.gov)
1999]. Few studies have been conducted of altered sex ratio with maternal exposure to persistent pollutants. (cdc.gov)
6-8 Because low sex ratios have been linked to reduced sperm quality and quantity, 9-11 some postulate that a low offspring sex ratio is an early indicator for exposure to reproductive hazards or damage to the male reproductive system. (health.mil)

This ratio is conventionally expressed to M/F and is influenced by a large number of factors, including stress. (uwi.edu)
Sex ratio is conventionally defined as the proportion of male to female live births in a given population. (health.mil)

2-4 In the U.S., the sex ratio at birth decreased from 1.055 in 1940 to 1.048 in 2002;1 in 2016, the sex ratio of all live born U.S. infants was 1.047. (health.mil)

Two biological factors are important for understanding sex differences: sex hormones and sex chromosome effects ( McCarthy and Arnold, 2011 ). (jneurosci.org)

A national survey found that although 89% of secondary school students receive sex education at least once in school, only 68% receive information on how to use condoms correctly. (guttmacher.org)

Thus, the behavior difference between the groups more likely reflects a G × E interaction, that is, the influence of specific genetic variants manifesting under specific environmental conditions (kennel life). (frontiersin.org)
In nonhuman species, testosterone is known to have permanent organizing effects early in life that predict later expression of sex differences in brain and behavior. (jneurosci.org)

Offspring sex ratio is often used in demographic, environmental, and occupational studies to assess the impact of certain exposures on reproductive and endocrine health. (health.mil)
The high levels of support for comprehensive sex education across California's diverse regions and demographic subgroups suggest that such support may be generalizable to communities and school districts both in California and around the country. (guttmacher.org)

There was an association between sickness absence and sex segregation, in different directions at the occupational and work site level. (bmj.com)
In one of the first studies of sex segregation and health, Hall 1 found that men in male dominated, white collar jobs had the highest work control of all groups, while women in the same group had the second highest work control. (bmj.com)
5- 7 However, Hensing and colleagues 8 showed that sickness absence with psychiatric disorders, which to a lesser extent is related to physical workload, varied even more with sex segregation. (bmj.com)
Finally, it has been shown that sickness absence with pregnancy related disorders varied with regard to level of sex segregation in the different occupational groups. (bmj.com)

The male-to-female birth ratio varies seasonally. (uwi.edu)
Similarly, hemiplegic migraine is more common in women, with a male-to-female sex ratio of 1:3. (medscape.com)
Benign coital headache has a male-to-female ratio of 4:1. (medscape.com)

Migraine affects nearly 13% of the adult US population, with a postpubertal female-to-male ratio of 4:1. (medscape.com)
The offspring sex ratio of male submariners was 1.048, which did not substantially differ from the sex ratio of each comparison population. (health.mil)
Contrary to previous studies, this large, record-based analysis found no evidence to suggest the offspring sex ratio of male active duty U.S. Navy submariners is different from that of other active duty populations or the U.S. population as a whole. (health.mil)
This study assesses sex education preferences among California parents-a critical and understudied population of potentially influential stakeholders. (guttmacher.org)
however, in the pediatric population, this difference did not reach statistical significance, likely because of the small sample size and the wide range of observed values in the pediatric patients with nonfatal cases. (cdc.gov)

We created a genetic map for Begonia which allows us to see how many genes affect the differences between species in this huge group of tropical plants (over 1,500 species). (ed.ac.uk)

Results: During the growing season, the job strain ratio increased by 0.031 (95% CI: 0.012, 0.05) during drought conditions, an amount equivalent to a one-half standard deviation change (Cohen's D = 0.5), compared to non-drought conditions. (cdc.gov)

Sexes often experience different selection pressures leading to sex-specific allocation between reproduction and self-maintenance, facilitating divergence in life-history. (springer.com)
This would help us to understand the evolutionary pressures that shaped human gestation, gender differences, and relations between the sexes. (ox.ac.uk)

We investigate whether sexes differ in means and variances along the fast-slow pace-of-life continuum for life history and physiological and behavioral traits. (springer.com)
Odds of an active visit were significantly lower in non-Hispanic blacks than whites (odds ratio, 0.67) but did not significantly differ between Hispanics and non-Hispanic whites. (cdc.gov)

There is a difference between total and free testosterone. (undiagnosed-usa.org)
This ingredient naturally binds to Sex hormone binding globulin (SHBG) and causes a boost in free testosterone ratio. (undiagnosed-usa.org)
Another supplement that will increase free testosterone by binding to SHBG (sex hormone binding globulin). (undiagnosed-usa.org)

Past research on pediatric cancer incidence described differences by U.S. Census region but did not provide state-level estimates (4). (cdc.gov)
State-based differences in pediatric cancer incidence could guide interventions related to accessing care (e.g., in states with large distances to pediatric oncology centers), clinical trial enrollment, and state or regional studies designed to further explore variations in cancer incidence. (cdc.gov)

In comparison with participants without disease, the odds ratio of cessation for those diagnosed with cancer was markedly large (OR = 27.5). (bmj.com)
PF was calculated as one minus odds ratio. (lu.se)

A longitudinal linear mixed effects model was used to estimate the change in job strain ratio, a continuous metric of occupational psychosocial stress , during drought conditions measured with a 12-month standardized precipitation index. (cdc.gov)
We further evaluated associations between drought and psychological job demand and job decision latitude, the job strain components, and applied a stratified analysis to evaluate differences by participant sex, age, and geography. (cdc.gov)
The association between drought and the job strain ratio was driven mostly by increases in the psychological job demand (2.09;95% CI: 0.94, 3.24). (cdc.gov)

It is less understood that sex differences have been converging, particularly among certain subgroups and causes. (bmj.com)

To study completed suicides across all ages of AI/AN, NVDRS data collected from 2003 to 2014 were analyzed by comparing differences in suicide characteristics and circumstances between AI/AN and white decedents. (cdc.gov)
In addition, we test whether social and environmental characteristics such as breeding strategy, mating system, and study environment explain heterogeneity between the sexes. (springer.com)
Scholars such as Michael Gottfredson and Travis Hirschi argue that the age-crime curve is essentially invariant across subpopulations based on sex, race, income, and other characteristics, and cannot be explained by social processes that vary across age. (encyclopedia.com)
Characteristics such as age, sex, race, household relationship, and Spanish origin are shown for each person in the household enumerated. (cdc.gov)

To assess if the behavioral difference between the family and kenneled dogs could be due to genetic divergence of these two populations and/or to lower genetic diversity of the kenneled dogs, we analyzed their genetic structure using 11 microsatellite markers. (frontiersin.org)
We found no significant difference between the populations in their genetic diversity (i.e., heterozygosity, level of inbreeding), nor any evidence that the family and kenneled populations originated from different genetic pools. (frontiersin.org)
There were difficulties in obtaining exact genetic sex ratios. (scialert.net)

The sex ratio at birth is in overall decline in Europe and North America. (uwi.edu)

The phrase "comprehensive sex education" is commonly used in policy debates and by the media to distinguish approaches that cover contraception and protection from those that strategically omit these topics. (guttmacher.org)

Israel has been shown to have a relatively stable M/F. This study was carried out in order to ascertain whether there were any racial or religious differences in M/F in Israel, and to compare with totals for Europe and North America. (uwi.edu)
1,2 Though considered a stable measure, sex ratio has steadily declined in most North American and European countries over the past several decades, albeit modestly. (health.mil)

The conclusions suggest that embryonic death is bound up with the embryo's sex in ways that are not yet fully understood. (ox.ac.uk)

The smallest difference in sickness absence was found in occupational groups with a relatively equal sex distribution (40-60% of either sex). (bmj.com)
12 A 2004 survey-based study did not corroborate this finding, but it did report a decrease in offspring sex ratio with additional time in the submarine community and detected lower sex ratios among submariners with certain naval ratings (i.e., occupational specialties), such as sonar technicians. (health.mil)

Number, age, and sex ratio of participants were also obtained when available. (psychiatrist.com)

A group of 720 sex and much distress. (who.int)

Cross-tabulations and odds ratios were used to assess regional and other subgroup differences. (guttmacher.org)

The aim of the present study was to explore differences in the clinical expression, clinical diagnoses and management of airway diseases in a primary-care setting. (ersjournals.com)
The present study explores differences in clinical expression of airway disease, diagnoses and management in a primary-care setting. (ersjournals.com)

These data do not contain information on race/ethnicity and thus do not reflect whether sex-specific trends differentially affected certain racial/ethnic groups over time. (bmj.com)

In all continents, latitude gradients and secular trends have been found in the male-female ratio at birth (M/F: male births divided by total births), which is anticipated to approximate 0.515. (uwi.edu)
Östlin and colleagues 3 studied myocardial infarctions and found a higher risk for both women and men in sex segregated occupations. (bmj.com)

Dose-related growth depression occurred in both sexes at and above 100 mg/kg body weight/day throughout all three generations and in F 0 and F 2 males even at 25 mg/kg body weight/day. (inchem.org)

One study noted that children fathered by men exposed to dioxin after the Seveso, Italy accident showed a decrease in the expected male:female ratio [Mocarelli et al. (cdc.gov)

A dose-dependent differences was recorded in relative liver weights. (europa.eu)
Note: The NOAEL/BMDL (or, in some cases lowest observed adverse effect level) are used in this analysis, NOT the agency RfD or MRL, because of differences in purpose and dose adjustments. (cdc.gov)

This study's null findings suggest that submariners are not likely exposed to reproductive hazards in the workplace that alter offspring sex ratio. (health.mil)
Changes in sex ratio can have enormous social ramifications: there are parts of the world where sex ratios are being distorted by parents intentionally choosing boys, and changes are introduced perhaps inadvertently by reproductive technologies. (ox.ac.uk)

All equal to the total number of students in the of these may predispose to a number of test group and comparable regarding age, skin problems that can add to the child's sex and usual residence of their families. (who.int)
No risk differences were observed by sex, age group, or geographic region. (cdc.gov)

Male live births occur in excess of female live births and their ratio (M/F) is usually expressed as male divided by total births. (uwi.edu)
The greater ratio of boys being born (around 51-52% of live births) has been known since the 17th century. (ox.ac.uk)

This differs from physical sex ratio which simply includes all individuals, including those that are sexually inactive or do not compete for mates. (wikipedia.org)
The OSR is said to be biased toward a particular sex when sexually ready members of that sex are more abundant. (wikipedia.org)
Ongoing and sometimes rancorous policy debates at the federal, state and local school district levels focus on the relative merits of sex education that teaches abstinenceonly until marriage versus approaches that include instruction on contraception and protection against STDs for students who do become sexually active. (guttmacher.org)
1-6 Despite such support, much of the sex education provided by American schools is minimal and fragmented, with essential topics often omitted or inaccurately presented, especially those related to methods of contraception and STD protection for sexually active youth. (guttmacher.org)

Specifically, we show how a shift toward a more companionate marital ideal among women from 2 migrant-sending communities in Mexico has created generational differences in women's attitudes toward men's sexual infidelity, and we argue that a growing emphasis on sexual intimacy within marriage may cause young Mexican women to be particularly invested in ignoring evidence of infidelity. (aphapublications.org)

Differences in patterns by birthplace may be explained by the Australian assisted-migration programme of 1945-1981. (bmj.com)
No differences in waning patterns in PF vac were seen between virus variants, gender, and age. (lu.se)

Phenotypic variances were similar between the sexes across trait categories and were not affected by mating system or study environment. (springer.com)

There are striking differences in schooling, jobs and health outcomes across social groups in the state. (worldbank.org)

The operational sex ratio is affected by the length of time each sex spends in caring for young or in recovering from mating. (wikipedia.org)
If it takes one sex longer to mature than the other, it would be expected to see a biased OSR of the sex that matured faster, most of the time. (wikipedia.org)
Bureau of Labor Statistics, U.S. Department of Labor, The Economics Daily , Median usual weekly earnings of full-time wage and salary workers by occupation and sex at https://www.bls.gov/opub/ted/2015/median-usual-weekly-earnings-of-full-time-wage-and-salary-workers-by-occupation-and-sex.htm (visited September 24, 2023 ). (bls.gov)
This is attributed to differences in flowering time in the male and female plants. (scialert.net)
It will also help boost libido and shorten refractory period (time between sex). (undiagnosed-usa.org)
Although most American students receive some type of sex education by the time they leave high school, 4 only about 5-10% receive complete and high-quality comprehensive sex education. (guttmacher.org)

As the OSR becomes more biased, the sex that is in excess will tend to undergo more competition for mates and therefore undergo strong sexual selection. (wikipedia.org)

The difference of two or more religious, ethnic and social communities can sometimes produce clashes in the society. (moviecultists.com)
The observed change in sex ratios has implications for healthcare and social systems. (bmj.com)

These data do not demonstrate the strong and significant changes in sex ratio observed elsewhere. (bmj.com)
There were no significant differences between the IBSD and IBSC groups in their cognitive appraisal of IBS symptoms. (springer.com)

This paper fails to find evidence of stress using the gender ratio at birth in Israel, when the country is studied by race or religion. (uwi.edu)

But what happens to the sex ratio in the first half of pregnancy has been essentially unknown. (ox.ac.uk)

As shown in Table 1, this ratio varies widely. (who.int)

Any sexual differences in the PRR will also change the OSR, so it is important to look at factors that change PRR as well. (wikipedia.org)
Sex chromosomes also exert an important additional influence on sexual differentiation. (jneurosci.org)
These categorical differences were eliminated in the DSM-5 to encourage the understanding that medical disorders and sleep disorders are intertwined and primary causation is usually not important. (medscape.com)

Anatomy2

Organisms3

Diseases1

Analytical, Diagnostic and Therapeutic Techniques and Equipment3

Psychiatry and Psychology6

Phenomena and Processes13

Anthropology, Education, Sociology and Social Phenomena4

Information Science1

Named Groups1

Health Care7

Geographicals1

Females11

Statistically significant2

Analyse3

Variation4

Prevalence4

Human sex r2

Mortality5

Logistic4

Respondents1

Predominant1

Exposure4

Conventionally2

20161

Hormones1

Secondary1

Behavior2

Demographic2

Segregation4

Male-to-fem3

Population5

Species1

0.051

Pressures2

Differ2

Testosterone3

Incidence2

Odds ratio2

Strain3

Subgroups1

Characteristics4

Genetic3

Decline1

Commonly1

Stable2

Understood1

Occupational2

Participants1

Distress1

Assess1

Expression2

Racial1

Found2

Depression1

Decrease1

Dose2

Reproductive2

Group2

Live births2

Sexually4

Women's1

Patterns2

Study1

Health1

Time6

Excess1

Social2

Significant2

Race1

Pregnancy1

Varies1

Important3