Social,biological, and political considerations on fertility in Arab populations

In analyzing fertility in the Arab countries, crude birth rate, total fecundity rate, and age specific fertility rates were measured. The data was obtained from United Nations, UNICEF, and the World Bank. In the early 1980's 13 of the countries had birth rates 40/1000. The majority of countries showed a decline in their crude birth rate (CBR) between 1960-83, except Somalia, which increased. The United Arab Emirates (UAE), Tunisia, Lebanon, and Kuwait, had the largest CBR decreases, followed by Morocco, Egypt, and Saudi Arabia. The global fecundity rate (GFR) shows the number of expected births a woman lives through her reproductive period, having children at the prevailing rate for each age. The GFR in these countries is much higher than those of non Moslem countries in the area. Results show that the fertility of Arab countries are in a gradual decline, but remain high, and many have a CBR over 40/1000. In the last 20 years Saudi Arabia, with the largest population of oil producing countries, has had a decreasing CBR. It is not in agreement with its high GFR, but this can be attributed to the large number of immigration workers in the country. The UAE showed a decrease in CBR from 46/1000 to 27/1000, the largest decrease in these countries. This decline coincided with the economic development due to oil production. Kuwait had a 25.5% decrease in CBR but less than Tunisia and Lebanon. The fertility decline in Kuwait intensified in the middle 1970's; the decline in northern Africa began in the late 1960's. There were declines in birth rates in the North African countries in the early 1970's except for Tunisia. The rapid declines in fertility can be attributed to the countries' socioeconomic and political situations.     

Sterilization and union instability in Brazil

Brazilian women rely on sterilization as the main source of birth control. Sterilization has been one of the causes of the steep decline in fertility in Brazil, at least since the second half of 1970. It is hypothesized that understanding couples' relationships might be key to explaining this high rate of female sterilizations. Possible reasons for the higher level of fertility among women in unstable unions than among women in stable ones could be the less effective use of contraceptive methods, or that women in unstable unions tend to use less effective or reversible contraceptive methods. In this paper discrete time modelling of the timing of sterilization according to union histories is presented. The analysis uses the calendar data of the 1996 Brazilian DHS. It is shown that women in second or higher order unions have a lower risk of sterilization. This result should be taken into account in the analysis of the determinants of female sterilization in Brazil.     

Fertility and patterns of labor force participation among married women

Abstract

Past research has shown that the labor market behavior of wives is discontinuous and affected by family events. Specifically, both cross‐sectional and panel data indicate that fertility decreases the period that a married woman spends working. Each birth appears to decrease labor force participation by one year or more. The present study attempts to specify these effects more completely. The variation in work patterns for each parity progression is examined to determine whether the fertility‐work effect is due to a few women who leave the labor force for an extended period during childbearing or due to a large number of women who have intermittent work histories. The analysis uses a national sample of women who were high school sophomores in 1955 and followed up as adults in 1970 and for whom retrospective data for each of the intervening years were obtained. Only married women with uncomplicated marital histories are included in the present study. We find dramatic evidence for two distinct types of response to childbearing. Women tend either to work almost continuously throughout the period or to drop out of the labor force for a very extended period of time after first birth.     

Fertility and the aging male

In the United States since 1980, the birth rate in women aged > 35 years has increased by nearly 60%, whereas the birth rate for women aged 20 to 34 years has increased by only 10%. The trend in parenthood at an older age has also been seen in men. Since 1980, the fertility rate for men in their 30s has increased by 21% and for men aged 40 years and older, the rate has increased nearly 30%. In contrast, the fertility rate in men younger than age 30 years has decreased by 15%. Age-related infertility will continue to be a problem. A basic understanding of the issues is critical for health care professionals so that they can effectively counsel patients who are considering a delay in childbearing for social reasons or for those seeking fertility treatments. This review details the changes in fertility seen in the aging male.     

The Brazilian Preference: Cesarean Delivery among Immigrants in Portugal

Objective

To evaluate how the country of origin affects the probability of being delivered by cesarean section when giving birth at public Portuguese hospitals.

Study Design

Women delivered of a singleton birth (n = 8228), recruited from five public level III maternities (April 2005–August 2006) during the procedure of assembling a birth cohort, were classified according to the country of origin and her migration status as Portuguese (n = 7908), non-Portuguese European (n = 84), African (n = 77) and Brazilian (n = 159). A Poisson model was used to evaluate the association between country of birth and cesarean section that was measured by adjusted prevalence ratio (PR) and respective 95% confidence intervals (95%CI).

Results

The cesarean section rate varied from 32.1% in non-Portuguese European to 48.4% in Brazilian women (p = 0.008). After adjustment for potential confounders and compared to Portuguese women as a reference, Brazilian women presented significantly higher prevalence of cesarean section (PR = 1.26; 95%CI: 1.08–1.47). The effect was more evident among multiparous women (PR = 1.39; 95%CI: 1.12–1.73) and it was observed when cesarean section was performed either before labor (PR = 1.43; 95%CI: 0.99–2.06) or during labor (PR = 1.30; 95%CI: 1.07–1.58).

Conclusions

The rate of cesarean section was significantly higher among Brazilian women and it was independent of the presence of any known risk factors or usual clinical indications, suggesting that cultural background influences the mode of delivery overcoming the expected standard of care and outcomes in public health services.     

Sequence analysis of the 2009 pandemic influenza A H1N1 virus haemagglutinin gene from 2009-2010 Brazilian clinical samples

In this paper, we analysed the haemagglutinin (HA) gene identified by polymerase chain reaction from 90 influenza A H1N1 virus strains that circulated in Brazil from April 2009-June 2010. A World Health Organization sequencing protocol allowed us to identify amino acid mutations in the HA protein at positions S220T (71%), D239G/N/S (20%), Y247H (4.5%), E252K (3.3%), M274V (2.2%), Q310H (26.7%) and E391K (12%). A fatal outcome was associated with the D239G mutation (p < 0.0001). Brazilian HA genetic diversity, in comparison to a reference strain from California, highlights the role of influenza virus surveillance for study of viral evolution, in addition to monitoring the spread of the virus worldwide.     

Canadian fertility trends in perspective

This paper examines the broad movements of Canadian period and cohort fertility over the past 100 years, and compares them with corresponding trends in the US and other industrialized countries. The main movement in Canada was a decline in fertility extending from the 19th century to the present, interrupted in the 1940s and 1950s by a baby boom. Between 1871 and 1937 the total fertility rate (TFR) fell at about an average of 1.4% annually. The rate of fall in the US was similar, with the result that in the late 1930s the Canadian TFR was about 20% that of the US. The fertility boom that followed was steeper in the US than in Canada, and in the downswing that later followed, the rate of decline was similar in the 2 countries (3.4-4% annual average). But, the decline continued longer-- indeed still continues--in Canada, whereas the TFR in the US reached its lowest point in 1976. Moreover, the recent decline in fertility has been more severe in Canada than in almost any other industrialized country. The TFR relates to fertility in a single year and is highly sensitive to short-term changes in the timing of births. For the purposes of understanding and explaining long-term trends in fertility, the completed fertility rate (CFR) is a better index because it measures the ultimate family size of cohorts. Cohort fertility can be seen to fluctuate much less than does period fertility. In both the US and Canada, the peak cohorts, born in the early 1930s, had roughly the same completed fertility, and later cohorts continued to remain closely in step as the CFR fell sharply. In Canada the fall continues, though at a reduced rate, in the latest cohorts for which there is information. Apart from differences in amplitude, the dates of turning points and the shapes of the TFR and CFR curves of Canadian fertility are fairly similar. The long decline in cohort fertility is largely explained by the decrease in the proportions of families of 6 or more children. During the baby boom, for Catholics and non-Catholics alike, the proportion of ever-married women remaining childless fell by about 40%, the proportion having 2 children changed little, and the proportions having 3,4 and 5 children tended to increase substantially. The crucial difference between the 2 groups was in the proportions of women having 6 or more children. For non-Catholics, the proportion fell by over 4% from a high level. For non-Catholics, on the other hand, the proportion rose somewhat, though even after the rise, it was barely more than 1/2 the level to which the Catholic proportion had declined. Among Catholics, the effect of the massive decline in the proportion of women having 6 or more children was to swamp the effects of the increase in the proportions of women having 3, 4 and 5 children. The net effect was that fertility declined. Among non-Catholics, however, the comparable increases in the proportions of families of 3, 4 and 5 children, were not offset by any fall in the proportion of larger families, with the result that a baby boom occurred.     

Breast cancer trends in women younger than 40 years in Brazil

BackgroundA recent Brazilian populational database analysis showed a concerning increase in breast cancer mortality rates among patients under 40 years. We aimed to evaluate the trends in the proportion of new breast cancer cases and deaths occurring in patients younger than 40 years over the last decade in Brazil.MethodsWe evaluated all consecutive breast cancer patients treated from 2009 to 2020 in a Brazilian tertiary cancer center. The proportions of new cases and deaths in patients younger than 40 years was compared between two time periods (2015–2020 versus 2009–2014) using Chi-squared test. Linear regression was used to evaluate the trends in the proportion of new cases and deaths in young patients over the years.ResultsFrom 2009 to 2020, a total of 12,569 breast cancer patients started treatment at our institution; 1441 were younger than 40 years. From 2009 to 2014, 9.9% (95% CI 9.2–10.7%) were patients younger than 40 years compared to 12.9% (95% CI 12.1–13.8%) from 2015 to 2020. Similarly, the proportion of deaths among breast cancer patients younger than 40 years increased during the period (2009–2014: 9.6%, 95% CI 7.8–11.6%; 2015–2020: 12.4%, 95% CI 10.9–14%). The linear regression model showed a trend for an increasing proportion of new breast cancer cases occurring in patients under 40 years (P = 0.005). Proportion increased from 7.9% (95% CI 6.2–9.8%) in 2009 to 21.8% (95% CI 19.1–24.8%) in 2020. The trend for the increase in the proportion of deaths in this young population was also observed in the linear regression model (P = 0.01).ConclusionsThe proportion of new breast cancer cases and deaths among patients younger than 40 years has increased in a public Brazilian cancer center over the past decade. These results raise the concern for the need to reconsider primary and secondary prevention strategies for young women.     

Ineffective contraceptive use and its causes in a natural fertility population in southern Jordan

Based on our interview survey of 574 randomly selected married women from a rural population in the South Ghor district, Jordan, where traditional Arab customs have been persistently maintained, in this paper we analyze the age-specific marital fertility rates (ASMFRs) and contraceptive practices, especially the prevalence and duration of contraceptive use. The ASMFRs fitted the natural fertility pattern proposed by Coale and Trussell's model, and the total fertility rate was estimated to be 7.2. Even though the prevalence rate of modern contraceptive methods has reached 14.3%, because of the recent increase among young women in particular, the users had larger numbers of children than the nonusers and the duration of contraceptive use was short, especially at young ages (e.g., about 90% 24-month discontinuation probabilities in 15-19- and 20-24-year-olds). These ineffective contraceptive uses were related to traditional Arab norms, represented by the pooled proportion of "as many as possible" and "up to God" answers to the ideal number of children (70% of men and 30% of women).     

Fertility decline driven by poverty: the case of Addis Ababa, Ethiopia

Demographic transition theory states that fertility declines in response to development, thus wealth and fertility are negatively correlated. Evolutionary theory, however, suggests a positive relationship between wealth and fertility. Fertility transition as a result of industrialization and economic development started in the late 19th and early 20th centuries in Western Europe; and it extended to some of the Asian and Latin American countries later on. However, economic crises since the 1980s have been co-incident with fertility decline in sub-Sahara Africa and other developing countries like Thailand, Nepal and Bangladesh in the last decade of the 20th century. A very low level of fertility is observed in Addis Ababa (TFR=1.9) where contraceptive prevalence rate is modest and recurrent famine as well as drought have been major causes of economic crisis in the country for more than three consecutive decades, which is surprising given the high rural fertility. Detailed socioeconomic and demographic characteristics of 2976 women of reproductive age (i.e. 15-49 years) residing in Addis Ababa were collected during the first quarter of 2003 using an event history calendar and individual women questionnaire. Controlling for the confounding effects of maternal birth cohort, education, marital status and accessible income level, the poor (those who have access to less than a dollar per day or 250 birr a month) were observed to elongate the timing of having first and second births, while relatively better-off women were found to have shorter birth intervals. Results were also the same among the ever-married women only model. More than 50% of women currently in their 20s are also predicted to fail to reproduce as most of the unmarried men and women are 'retreating from marriage' due to economic stress. Qualitative information collected through focus group discussions and in-depth interviews also supports the statistical findings that poverty is at the root of this collapse in fertility. Whilst across countries wealth and fertility have been negatively correlated, this study shows that within one uniform population the relationship is clearly positive.     

Population based study of rates of multiple pregnancies in Denmark, 1980-94.

OBJECTIVE: To study trends in multiple pregnancies not explained by changes in maternal age and parity patterns. DESIGN: Trends in population based figures for multiple pregnancies in Denmark studied from complete national records on parity history and vital status. POPULATION: 497,979 Danish women and 803,019 pregnancies, 1980-94. MAIN OUTCOME MEASURES: National rates of multiple pregnancies, infant mortality, and stillbirths controlled for maternal age and parity. Special emphasis on primiparous women > or = 30 years of age, who are most likely to undergo fertility treatment. RESULTS: The national incidence of multiple pregnancies increased 1.7-fold during 1980-94, the increase primarily in 1989-94 and almost exclusively in primiparous women aged > or = 30 years, for whom the adjusted population based twinning rate increased 2.7-fold and the triplet rate 9.1-fold. During 1989-94, the adjusted yearly increase in multiple pregnancies for these women was 19% (95% confidence interval 16% to 21%) and in dizygotic twin pregnancies 25% (21% to 28%). The proportion of multiple births among infant deaths in primiparous women > or = 30 years increased from 11.5% to 26.9% during the study period. The total infant mortality, however, did not increase for these women because of a simultaneous significant decrease in infant mortality among singletons. CONCLUSIONS: A relatively small group of women has drastically changed the overall national rates of multiple pregnancies. The introduction of new treatments to enhance fertility has probably caused these changes and has also affected the otherwise decreasing trend in infant mortality. Consequently, the resources, both economical and otherwise, associated with these treatments go well beyond those invested in specific fertility enhancing treatments.     

The association between HIV and fertility in a cohort study in rural Tanzania

Recent studies in sub-Saharan Africa have shown that fertility is reduced among HIV-infected women compared with uninfected women. The size and pattern of this fertility reduction has important implications for antenatal clinic-based surveillance of the epidemic and also for estimates and projections of the demographic impact of the epidemic. This paper examines the association between HIV and fertility in Kisesa, a rural area in Tanzania, where HIV prevalence among adults is about 6% and gradually increasing. The analysis is based on data obtained through a demographic surveillance system in Kisesa during 1994-98 and two large sero-surveys of all residents in 1994-95 and 1996-97. The HIV-associated fertility reduction among women was investigated by estimating fertility rates by HIV status and prevalence rates by fertility status. A substantial reduction (29%) was observed in fertility among HIV-infected women compared with HIV-uninfected women. The fertility reduction was most pronounced during the terminal stages of infection, but no clear association with duration of infection was observed. Use of modern contraception was higher among HIV-infected women. However, both among contracepting and non-contracepting women, a substantial reduction in fertility was seen among HIV-infected women.     

Female Employment Reduces Fertility in Rural Senegal

Economic growth and modernization of society are generally associated with fertility rate decreases but which forces trigger this is unclear. In this paper we assess how fertility changes with increased labor market participation of women in rural Senegal. Evidence from high-income countries suggests that higher female employment rates lead to reduced fertility rates but evidence from developing countries at an early stage of demographic transition is largely absent. We concentrate on a rural area in northern Senegal where a recent boom in horticultural exports has been associated with a sudden increase in female off-farm employment. Using survey data we show that employed women have a significantly higher age at marriage and at first childbirth, and significantly fewer children. As causal identification strategy we use instrumental variable and difference-in-differences estimations, combined with propensity score matching. We find that female employment reduces the number of children per woman by 25%, and that this fertility-reducing effect is as large for poor as for non-poor women and larger for illiterate than for literate women. Results imply that female employment is a strong instrument for empowering rural women, reducing fertility rates and accelerating the demographic transition in poor countries. The effectiveness of family planning programs can increase if targeted to areas where female employment is increasing or to female employees directly because of a higher likelihood to reach women with low-fertility preferences. Our results show that changes in fertility preferences not necessarily result from a cultural evolution but can also be driven by sudden and individual changes in economic opportunities.     

Site fidelity and movements of humpback whales (Megaptera novaeangliae) on the Brazilian breeding ground,southwestern Atlantic

Site fidelity and movements were studied for humpback whales photo-identified from 1989 to 2006 in the Abrolhos Bank, southwestern Atlantic, Brazil. A total of 2,612 individuals were identified, 374 of which were observed on more than one occasion. The cumulative number of identified whales has increased since 1989. Recapture rate was low and varied among different years. A total of 33 whales was observed using the Abrolhos Bank for longer than 10 yr, up to a maximum of 16 yr. Our data suggest that different whales show distinct movement rates. Some whales used a large extent of the Abrolhos Bank region. Opportunistic photo-identification data (on the scale of the Brazilian coast from 4° to 23°S) revealed important information about stock identity. The longest distance between within-season resightings was over 600 km, while one whale was observed in two locations separated by more than 1,400 km in different years. Long-range movements within and between seasons support the single stock hypothesis for humpback whales wintering off the Brazilian coast.     

Ilheus Virus Isolation in the Pantanal,West-Central Brazil

The wetlands of the Brazilian Pantanal host large concentrations of diverse wildlife species and hematophagous arthropods, conditions that favor the circulation of zoonotic arboviruses. A recent study from the Nhecolândia sub-region of Pantanal reported serological evidence of various flaviviruses, including West Nile virus and Ilheus virus (ILHV). According to the age of seropositive horses, at least three flaviviruses, including ILHV, circulated in the Brazilian Pantanal between 2005 and 2009. To extend this study, we collected 3,234 adult mosquitoes of 16 species during 2009 and 2010 in the same sub-region. Mosquito pool homogenates were assayed for infectious virus on C6/36 and Vero cell monolayers and also tested for flaviviral RNA by a group-specific real-time RT-PCR. One pool containing 50 non-engorged female specimens of Aedes scapularis tested positive for ILHV by culture and for ILHV RNA by real-time RT-PCR, indicating a minimum infection rate of 2.5 per 1000. Full-length genomic sequence exhibited 95% identity to the only full genome sequence available for ILHV. The present data confirm the circulation of ILHV in the Brazilian Pantanal.     

Demography, life history, and social structure in Propithecus diadema edwardsi from 1986-2000 in Ranomafana National Park, Madagascar

Prosimian lemurs differ fundamentally from anthropoid primates in many traits related to social structure. By exploring the demography of Milne-Edwards' sifakas (Propithecus diadema edwardsi), and comparing it to other well-studied primates, we explore the effect of demographic and life-history factors on social structure. Specifically, we compare lemur survivorship and fertility patterns to two published composite models: one created for New World and another created for Old World monkeys. Using longitudinal data collected on individual Propithecus diadema edwardsi from four study groups from 1986-2000 in Ranomafana National Park, Madagascar, we quantify 1) group composition, 2) birth seasonality, 3) interbirth interval, 4) life-table values, and 5) population growth estimates. The mortality, survivorship, and life-expectancy schedules indicate high infant and juvenile mortality. Fertility remains high until death. The intrinsic rate of increase and net reproductive rate indicate a shrinking population. We suggest that high mortality rather than low fertility causes the observed population decline. While sifaka survivorship closely resembles New World patterns, fertility resembles Old World patterns, i.e., like New World monkeys, few sifakas survive to reproductive age, and those that do, reproduce at a slow rate resembling the Old World pattern. This necessarily impacts social structure. An adult sifaka at the end of her lifespan will have one only daughter who survives to reproductive age, compared to 3.4 for New World or 2.7 for Old World monkeys. Demography limits the formation of large kin-based groups for sifakas, and survivorship and fertility patterns do not easily permit sifakas to form large same-sex family groups.     

Fertility preferences among Malaysian women: an analysis of responses to the new population policy

About 10% of 3887 ever-married women included in the 1984-85 Malaysian Population and Family Survey revealed that they were influenced by the new population policy to desire more children than they had originally wanted. These women were more likely to be rural Malays from the lower socioeconomic class. Ideal family size was more than four children. Children are desired for economic benefits and emotional support. The natality of the Malays has risen since 1980: their total fertility rate has increased while their contraceptive prevalence rate has dropped sharply. Coupled with a decline in the crude death rate, the present fertility preferences and behaviour of the Malays will render the target of the population policy more attainable than is reflected by the survey data.     

African heads of state promise action against malaria

Heads of state of Africa signed a pledge to reduce the continent's malaria mortality by 50% by 2110 at an international summit of Malaria in Abuja, Nigeria. The primary focus of the malaria control program will be insecticide-treated bednets. The WHO wants a 30-fold increase in the availability of bednets in the next 5 years, as well as immediate access to cheap and effective antimalarial combination therapy for families at risk of malaria, including pregnant women. Malaria control requires annual donations of US$1 billion from industrialized countries. However, donations alone will be insufficient unless there is immediate debt cancellation, says Jeffrey Sachs, director of the Center for International Development at Harvard. The World Bank also raised criticisms concerning the US$150 million annual donation. In response, Ok Pannenborg of the World Bank stated that there are 100 World Bank operations all over Africa and its US$150 million annual donation for African malarial control projects is money they can use, but whether they use it is another matter.     

Fertility in the mare after repeated transvaginal ultrasound-guided aspirations

Ovum pick-up (OPU) by transvaginal ultrasound guided aspiration (TUGA) is a procedure applied in equine-assisted reproduction programs such as oocyte transfer and in vitro embryo production. Despite a large number of studies reporting that it is a repeatable and safe technique, little information is available about the effect of repeated punctures on fertility of mares. Moreover, even if flushing follicles improves the oocyte recovery rate, to our knowledge the efficiency of flushing estrous and diestrous follicles has not been evaluated. The aims of the present study were (1) evaluate if repeated TUGAs negatively effects fertility and (2) investigate the influence of flushing the follicular cavity (as compared to aspiration only-unflushed) on the recovery rate from follicles of different sizes and in different stages of the estrous cycle. Seventy-six TUGAs were carried out on 20 mares during the breeding season; 153 follicles were aspirated and 31 oocytes were recovered (20.3% per follicle; 40.8% per TUGA attempt). Of the 76 aspirations, 52 were carried out during estrus and 24 in diestrus. Flushing the follicular cavity significantly increased (P < 0.01) the oocyte recovery rate from estrous follicles (13/28, 46.4% flushed versus 3/24, 12.5% aspirated only) but not (P > 0.05) from diestrous follicles of different diameters (3/30, 10% flushed versus 2/36, 5.6% aspirated only for follicles <2 cm in diameter; 6/20, 30% flushed versus 4/15, 26.7% aspirated only for follicles > or =2 cm in diameter). Mares underwent ultrasonic examinations after every aspiration and no alteration was found with the exception of two mares in which the corpus luteum (CL) did not form following aspiration of estrous follicle. Of the 20 mares involved in this study, 10 were artificially inseminated with fresh semen from a single fertile stallion at the first spontaneous heat following the previous aspiration. Of the 10 inseminated mares, 7 were found to be pregnant 16, 30 and 50 days after artificial insemination (AI), indicating that repeated TUGAs did not adversely affect fertility.     

Economics of selecting for sex: the most important genetic trait

Over 20,000 calves have resulted from artificial insemination (AI) of cattle with sexed, frozen/thawed sperm in the course of experimentation in several countries, and from commercial sales in the United Kingdom. This technology likely will become commercially available in many countries within a few years. Accuracy of the process is about 90% for either sex, and resulting calves appear to be no different from non-sexed controls in birthweight, mortality, rate of gain, and incidence of abnormalities. The main determinants of the extent of use of sexed sperm will be pregnancy rate and cost. Fertility of low doses (1.5 x 10(6)-2 x 10(6)) of sexed, frozen sperm for AI of heifers usually has been in the range of 70-80% of unsexed sperm at normal doses (10 x 10(6)-20 x 10(6) sperm) in well managed herds; it has been lower in poorly managed herds, and likely will be lower with lactating dairy cows. It is expected that fertility of sexed sperm will increase significantly due to very recent improvements in the hydrodynamics of the sexing process and potential improvements in cryopreservation procedures. It is unclear how sexed sperm will be priced; the cost of sexed sperm for cattle will likely be more than double the cost of unsexed sperm in most markets. The economic benefit of using sexed sperm also will depend on the baseline fertility of the herd since at lower fertility, it takes more doses of semen per calf produced. It is noted that for a small percentage of elite cattle, the economics of using sexed sperm do not depend primarily on increased production or efficiency of producing meat or milk, but rather on factors such as scarcity, tradition, cattle show winnings, and biosecurity during herd expansion. Until sorting efficiencies improve and costs decline, sales likely will be limited primarily to these niche markets. With near normal fertility and a premium for sexing in the range of US$ 10 per insemination dose, sexed sperm likely would become economically and environmentally beneficial for many, if not most populations of cattle being bred by AI.