Showing papers on "Fertility published in 1993"

The Gender Gap, Fertility and Growth

Abstract: This paper examines a novel mechanism linking fertility and growth. Household fertility is determined by relative wages of women and men. Increasing women's wages reduces fertility by raising the cost of children relatively more than household income. Lower fertility raises the level of capital per worker which in turn, since capital is more complementary to women's labor input than men's, raises women's relative wages. This positive feedback leads to the possibility of multiple steady-state equilibria. Countries with low initial capital may converge to a development trap with high fertility, low capital, and low relative wages for women.

The Gender Gap, Fertility and Growth

Abstract: Changes in fertility have long been recognized as important correlates of economic growth with the relationship between the level of fertility and the level of income per capita being one of the strongest observable correlations in cross-country data. This paper examines the linkages between fertility and growth theory. The structure of the model is presented in sections on production couples decision making system dynamics and steady-state equilibria. The first component of the model is that increases in capital per worker raise womens relative wages since capital is more complementary to womens labor input than to mens. The second component is that increasing womens relative wages reduces fertility by raising the cost of children more than household income. Finally lower fertility raises the level of capital per worker. A positive feedback loop generates demographic transition a rapid decline in fertility accompanied by accelerated output growth.

Fat and female fecundity: prospective study of effect of body fat distribution on conception rates.

Abstract: OBJECTIVES--To study the effect of body fat distribution in women of reproductive age on fecundity. DESIGN--Prospective cohort study of all women who had entered a donor insemination programme. SETTING--One fertility clinic serving a large part of the midwest of the Netherlands. SUBJECTS--Of 542 women attending the clinic for artificial insemination for the first time, 500 women were eligible for study. MAIN OUTCOME MEASURES--Probability of conception per cycle and number of insemination cycles before pregnancy or stopping treatment. RESULTS--A 0.1 unit increase in waist-hip ratio led to a 30% decrease in probability of conception per cycle (hazard ratio 0.706; 95% confidence interval 0.562 to 0.887) after adjustment for age, fatness, reasons for artificial insemination, cycle length and regularity, smoking, and parity. Increasing age was significantly related to lower fecundity (p < 0.05); very lean and obese women were less likely to conceive (p < 0.10) as were women with subfertile partners (p < 0.10). All other exposure variables were not significantly related to fecundity. CONCLUSIONS--Increasing waist-hip ratio is negatively associated with the probability of conception per cycle, before and after adjustment for confounding factors. Body fat distribution in women of reproductive age seems to have more impact on fertility than age or obesity.

Religion as a Determinant of Marital Stability

Abstract: This paper develops hypotheses about the effects of husbands’ and wives’ religious affiliations on fertility. The hypotheses are based on two central ideas. First, religions differ in their fertility norms and corresponding tradeoffs between the quality and quantity of children; differences in religious beliefs between husband and wife may thus lead to conflict regarding fertility decisions and possible resolution through bargaining. Second, a low level of religious compatibility between the spouses may raise the expected probability of marital dissolution and thereby decrease the optimal amount of investments in spouse-specific human capital. Analyses of data from the 1987—1988 National Survey of Families and Households conducted in the United States suggest that both of these effects play important roles in explaining the observed linkages between the religious composition of unions and fertility behavior.

A joint model of marital childbearing and marital disruption

Abstract: Married couples with children appear to be less likely to end their marriages than childless couples, especially when the children are young. Although this suggests that children affect the chances that their parents will divorce, the process may not be so simple: the chances that the marriage will last also may affect couples' willingness to make the commitment to the marriage implied by having children. This paper uses data from the Panel Study of Income Dynamics (PSID) to test the hypothesis that the risk of disruption faced by a married woman affects the chances that she will conceive and bear a child. The model used takes into account the simultaneous relationships between marital dissolution and marital fertility by including the hazard of disruption as a predictor of timing and likelihood of marital conception, and by including the results of previous fertility decisions as predictors of disruption of the marriage. We find that the hazard of disruption has strong negative effects on the hazard of marital childbearing, lengthening the intervals between births and decreasing the chances that a child will be born. This effect appears to be strongest for women who have had at least one child, either before or during the current marriage, although it is also large for childless women. Explicitly including the hazard of disruption in models of marital childbearing has sizable and important effects on many predictors of fertility.

Social Dynamics of Adolescent Fertility in Sub-Saharan Africa

Abstract: Adolescent fertility tends to be valued and sanctioned in the countries of sub-Saharan Africa when parents have had adequate ritual or training preparation for adulthood and the child has a recognized father. Young women and adolescents who conceive and bear children within this context are widely accepted by society; those who conceive outside of marriage however are strongly condemned by society. Over the past 2-3 decades most African countries have successfully raised their levels of education. Girls and women are increasingly privy to formal school education and training in trade apprenticeships domestic service and ritual initiation which had otherwise been denied in the past. These factors combined with declining menarche in a few areas and changing economic opportunities law and religion make it more difficult to define the exact date of entry into marriage. Many girls are taking advantage of these changing circumstances and their opportunities to obtain educations and resist early marriage and cildbearing. While defying the traditional entry into early marriage many young women do not however refrain from engaging in sexual activities. Pregnancies to unwed mothers are thereby on the rise and may constitute the most profound change observed in the social context of adolescent fertility on the continent. Once pregnant many women find themselves shut out by family planning programs and prenatal clinics which serve only married women. This paper ultimately concludes that the social context of adolescent childbearing has an effect on the outcome for mother and child which is as important as the physiological maturity of the mother.

Fertility and Employment

Abstract: This paper reviews the empirical evidence on the relationship between fertility and women's employment. In modern, industrialized societies there is generally a negative relationship between the two, but the causal direction is far from clear. No doubt, fertility exerts a negative influence on work-force participation, in the sense that a new-born baby has a dramatic and immediately inhibiting effect on work- force participation for the woman who has just become a mother. This effect tends, however, to be temporary and decreases as the child gets older. On the other hand, the effect of employment on fertility is a much more debated issue, and the author questions whether the presumed negative relationship really holds in most of contemporary Western Europe. The incompatibility of employment and motherhood would seem to have become seriously weakened in recent decades, through the growth of part-time work and the increasing availability of institutionalized child care. From a feminist perspective, it may be argued that the incompatibility of work and motherhood is mainly a consequence of existing gender structures in society and the ensuing power relations within marriage. Countries with modified gender structures would therefore seem to stand a better chance of achieving a birth rate near replacement level.

Cultural and Economic Approaches to Fertility : A Proper Marriage or a Mesalliance?

Abstract: Economic models have organized much fertility research particularly over the last 2 decades. The usual formulation of these models assumes that preferences are fixed and fertility differences are explained by differences in opportunities (constraints). Yet some interpretations of evidence of fertility decline inconsistent with economic models and have led to explicit challenges to them. These challenges generally take 2 forms--an emphasis on diffusion and an emphasis on culture. This paper addresses the consistency of the empirical findings and the interpretations drawn from then with economic models. In particular the authors discuss the roles that diffusion may play in economic models and the relationship between cultural and economic explanations of fertility. The fit between diffusion and economic models depends on what is diffusing. Here the literature is diffuse variously identifying new information new attitudes regarding ideal family size or the new values legitimating fertility control within marriage. The distinction is critical for the issue considered here since the diffusion of information about birth control technology is consistent with a household production model. Differences in information about opportunities can explain differences in behavior. The diffusion of preferences ( a new ideal family size or the new legitimacy of fertility control within marriage) on the other hand fits less comfortably within economic models although recent work suggests that it too can be accommodated. Cultural explanations fit rather awkwardly with economic models because culture cuts across the categories of opportunities (including information) and preferences thereby denying the validity of the dichotomous classification scheme underlying economic models. Finally culture may define the types of behaviors that are subject to individual choice in a particular society and thus delimit the areas within which economic or rational actor models are appropriate. (authors)

Public Policy as the Fuel of Fertility: Effects of a Policy Reform on the Pace of Childbearing in Sweden in the 1980s:

Abstract: In Sweden the total fertility rate (TFR) stopped declining in the late 1970s and started rising in the mid-1980s. The TFR exceeded the replacement level in 1990 and stayed above it in 1991. Characteristics of this recent fertility increase and the role of public policies are discussed. A technique called improved indirect standardization produced annual indexes of the level of childbearing at various birth orders. Swedish first-birth rates for single years of age for each calendar year from 1961 to 1990 were split into groups of ages. The rates al all ages below 30 generally fell from the mid-1960s through the early 1980s but there has been a mild recovery since 1984. At ages above 30 first-birth rates rose strongly in the 1980s as part of a steady postponement of the first birth to higher ages than before. About 82% of Swedish women who become mothers also had a second child and almost 40% of these also had a third child. Third-order birth rates increased up to the third year after the second birth and then declined steadily. The level of third and fourth birth rates fell from the mid-1960s to about 1977 and then recovered. The curves rose particularly strongly for mothers of children of age 1 with a further boost for this group starting about 1984. The strongly positive fertility gradient for age 1 of the youngest child and the corresponding break in 1986 for age 2 (but not age 2.5) may be a response to policy change. Recent fertility developments can be attributed to the muted pronatalism of social policies the growth of the day-care system and the extension of parental leave from 9 to 12 months. During the 1970s a premium on further childbearing was paid provided the interval between the 2 births did not exceed the period of statutory leave plus 6 months.

The diffusion of fertility control in Taiwan: evidence from pooled cross-section time-series models.

Abstract: This article assesses whether Taiwan's rapid fertility transition over the period 1960–1980 was facilitated by interpersonal diffusion. Annual data on some 361 areal units are available; these support the estimation of dynamic fixed-effect models of marital fertility. The statistical models take aim at the principal empirical prediction of diffusion hypotheses: the implication of autoregressive behaviour in fertility. We test for autoregressive effects over time within areas, and also for spatial effects whereby fertility control in one geographical area has a spillover influence on another. The Taiwanese data produce clear evidence in support of within-area diffusion. The evidence for cross-area diffusion is much weaker; there is surprisingly little suggestion of city-to-country diffusion. The estimates imply that interpersonal diffusion amplified the impact of Taiwan's family planning programme on fertility.

Culture, the Status of Women, and Demographic Behaviour: Illustrated with the Case of India

Abstract: The field area and its inhabitants the status of women fertility infant and child mortality sex differences in physical well-being.

Demographic Change in Sub-Saharan Africa

Abstract: This report is one in a series of studies that have been carried out under the auspices of the Panel on the Population Dynamics of Sub-Saharan Africa of the National Research Council (NRC) Committee on Population. This volume contains eight papers produced by the panel. The papers review "levels and trends of fertility the proximate determinants of fertility nuptiality child mortality; adult mortality; internal migration; and international migration as well as the demographic consequences of the AIDS epidemic." (EXCERPT)

Marriage and cohabitation following premarital conception.

Abstract: The role of cohabitation in the legitimation of premarital conceptions is considered using data on a sample of 920 women from the [U.S.] National Survey of Families and Households....Cohabitation does not appear to be a substitute for marriage....Findings indicate that cohabitation is part of the legitimation process and that it influences white womens and black womens marital behavior differently. This is a revised version of a paper originally presented at the 1992 Annual Meeting of the Population Association of America. (EXCERPT)

Fertility and pregnancy after treatment for cancer during childhood or adolescence.

Abstract: Because most children and adolescents with cancer now survive, issues regarding the late effects of therapy, including fertility and the health of offspring, are increasingly important. This article summarizes the literature regarding issues related to fertility in survivors of cancer, including actual fertility, gonadal function, menarche, menopause, and birth defects and cancer in the offspring. Radiation therapy to the gonads and alkylating agent chemotherapy, either alone or in combination, impair actual fertility in survivors of childhood and adolescent cancer. Males are particularly affected by alkylating agents, and females who have had radiation therapy to the abdomen have decreased fertility and an increased risk of adverse pregnancy outcomes. Consequently, these women should be followed up as high-risk obstetrical patients. Offspring of survivors of cancer appear to have little risk of childhood cancer or birth defects. Thus, in most instances, survivors of cancer should not be discouraged from having children and can expect a good outcome of pregnancy. This article concludes with advice to survivors and clinicians who counsel survivors.

Sperm morphology and fertility in the dog.

Abstract: Normal and abnormal dog spermatozoa were studied by means of bright field light and transmission electron microscopy and the effect of abnormal spermatozoa on dog fertility was evaluated. Semen samples were collected by digital manipulation from 67 dogs of 34 different breeds. Ten of the samples were examined ultrastructurally. The association between the percentage abnormal spermatozoa in the ejaculate and the fertility of the dog was statistically evaluated, based on insemination of 42 bitches. On this basis, the male dogs were divided into normal and subnormal groups. The percentage normal morphology below which fertility was adversely affected was found to be 60%: the fertility of dogs with > 60% normal morphology was 61% (14 of 23 inseminated bitches) whereas the fertility of dogs with < 60% normal morphology was 13% (two of 15 inseminated bitches). There was no statistical difference between the ages of the dogs in the two groups; from this it was concluded that subfertility may affect a dog at any age.

The South African Fertility Decline

Abstract: There is some evidence to suggest that Black South African started to decline in 1960 which was earlier than anywhere else in Black Africa. The Black South African population is larger than any Black population in Africa with the exception of Nigeria Ethiopia and Zaire. The national population program was an Asian-type program distinguished by expenditures and services not evident elsewhere in Africa. Clinical family planning (FP) services were densely located to provide better coverage than is available anywhere in the world. Contraceptive prevalence was around 60% for women overall and 50% for Black women in the 1990s. The FP program difference was in its lack of ability to mobilize the whole community. A lengthy discussion is provided of the early (pre-1963) demand for fertility control among different racial groups government intervention in its impact the relevance of the South African experiences to other parts of Africa and the implications of democratization efforts and majority Black rule. The Black population lives in an urban industrialized economy with an income level among the highest of African countries. Primary schooling is universal and 60% attend secondary school. Fertility data on the Black population are available from the fertility survey in 1974 and 1987-88. From these and other studies it appears that the White population followed a pattern similar to the Western model. Africaner fertility was higher than White fertility until about the 1960s and then followed a similar pattern. Indian Colored and Black women had a constant fertility of 6-7. Colored fertility began to decline after 1960 Indian after 1940 and Blacks in the 1970s and 1980s to rapidly reach 4.6 in 1989. The exact level of Black fertility is still somewhat in doubt. Population policy is demarcated by periods before 1963. 1963-74 (government intervention) 1974-83 (National FP Program) and from 1984 (the Population Development Program). Experience indicates that once there is demand for fertility control a FP program can lead to a decline in fertility but a fragile demand limits even the best FP program. Sociocultural resistance is stronger than that encountered in Asia and democratization and the political position of the African National Congress will bring about a reduction in funding but a broader popular identification for the FP program. As socioeconomic opportunities for Blacks increase it is likely that fertility will continue to fall.

Social Gains from Female Education: A Cross-National Study

Abstract: The authors explore the strength of female secondary education relative to, and in combination with, family planning and health programs in reducing fertility and infant mortality. They find that family planning and health programs do influence fertility and mortality, but that the impact of expanding female secondary enrollments appears to be much greater, especially in countries with low female secondary enrollment. Fertility and infant mortality are more elastic with respect to female secondary education than to family planning and health programs. Their simulations suggest the following. Doubling female secondary school enrollment (from 19 to 38 percent) in 1975 would have reduced the total fertility rate in 1985 from 5.3 to 3.9. Doubling the family planning service score (from 25 to 50 percent) in 1982 would have reduced the total fertility rate only from 5.5 to 5.0. Doubling female secondary school enrollment in 1975 from 19 to 38 would have reduced the infant mortality rate from 81 to 38. Halving the ratio of population per physician would have reduced the infant mortality rate only from 85 to 81. Doubling per capita GDP from $650 to $1,300 would have reduced the infant mortality rate only from 98 to 92. Doubling female secondary school enrollment (from 19 to 38) in 1975 would have lowered the number of births by 29 percent of the 1985 number. Doubling family planning services would have reduced it by 3.5 percent. Doubling female secondary school enrollment would have reduced infant deaths by 64 percent. Halving the ratio of population per physician would have reduced it only by 2.5 percent. Doubling per capita GDP has no effect on reducing infant deaths, all other factors being constant. Female education affects desired family size by raising the opportunity cost of a woman's time in economic activities, increasing demand for family planning, and promoting more effective contraceptive use.

Age, pregnancy and miscarriage: uterine versus ovarian factors.

Abstract: This study was performed to evaluate the relative contribution of oocyte and uterine factors to the age-related reduction in fecundity. The pregnancy and miscarriage rates in women receiving donated oocytes were compared to those in women using their own oocytes in in-vitro fertilization (IVF) and gamete intra-Fallopian transfer (GIFT) procedures. Oocyte donation with embryo transfer was performed on 241 women in 371 cycles; 116 of these women became pregnant (48% per patient and 31.5% per cycle) of whom 40 (35%) miscarried, giving a live birth rate of 20.5%. Assisted conception, in the form of IVF/GIFT procedures, was performed on 1331 women using their own oocytes in 2194 cycles; 627 of these women became pregnant (47% per patient and 28.7% per cycle), of whom 228 (36%) miscarried, giving a live birth rate of 18.2%. Neither the age of the donor nor the age of the recipient was related to pregnancy rate. The age of the donor, however, was directly related to the miscarriage rate. On the other hand, the age of patients undergoing IVF/GIFT was inversely related to the pregnancy rate and directly related to the miscarriage rate. In women of 40 years or over, the overall pregnancy and live birth rates were significantly higher and the miscarriage rate was significantly lower in the group receiving donated oocytes compared to the group using their own oocytes. In summary, we suggest that the age-related decline in fecundity is associated with the age of the oocytes rather than the age of the uterus.

Environment, human reproduction, menopause, and andropause.

Abstract: As the hypothalamic gonadotropin-releasing hormone (GnRH) pulse generator is an integrator of hormonal, metabolic, and neural signals, it is not surprising that the function of the hypothalamogonadal axis is subject to the influence of a large array of environmental factors. Before puberty, the central nervous system (CNS) restrains the GnRH pulse generator. Undernutrition, low socioeconomic status, stress, and emotional deprivation, all delay puberty. During reproductive life, among peripheral factors that effect the reproductive system, stress plays an important role. Stress, via the release of corticotropin-releasing factor (CRF), eventually triggered by interleukin 1, inhibits GnRH release, resulting in hypogonadism. Effects of CRF are probably mediated by the opioid system. Food restriction and underweight (anorexia nervosa), obesity, smoking, and alcohol all have negative effects on the GnRH pulse generator and gonadal function. Age and diet are important determinants of fertility in both men and women. The age-associated decrease in fertility in women has as a major determinant chromosomal abnormalities of the oocyte, with uterine factors playing a subsidiary role. Age at menopause, determined by ovarian oocyte depletion, is influenced by occupation, age at menarche, parity, age at last pregnancy, altitude, smoking, and use of oral contraceptives. Smoking, however, appears to be the major determinant. Premature menopause is most frequently attributable to mosaicism for Turner Syndrome, mumps ovaritis, and, above all, total hysterectomy, which has a prevalence of about 12-15% in women 50 years old. Premature ovarian failure with presence of immature follicles is most frequently caused by autoimmune diseases or is the consequence of irradiation or chemotherapy with alkylating cytostatics. Plasma estrogens have a physiological role in the prevention of osteoporosis. Obese women have osteoporosis less frequently than women who are not overweight. Early menopause, suppression of adrenal function (corticoids), and thyroid hormone treatment all increase the frequency of osteoporosis. Aging in men is accompanied by decreased Leydig cell and Sertoli cell function, which has a predominantly primary testicular origin, although changes also occur at the hypothalamopituitary level. Plasma testosterone levels, sperm production, and sperm quality decrease, but fertility, although declining, is preserved until senescence. Stress and disease states accelerate the decline on Leydig cell function. Many occupational noxious agents have a negative effect on fertility.(ABSTRACT TRUNCATED AT 400 WORDS)

The fertility of agricultural and non-agricultural traditional societies.

Abstract: A comparison of demographic data from a sample of traditional, natural-fertility societies demonstrates that the mean total fertility of populations which practise intensive agriculture is significantly higher than that of foragers and horticulturalists. These findings support the association that demographers and economists have long maintained between the intensification of subsistence technology and increases in human fertility. This higher fertility probably results from changes in nutritional status, marriage patterns, and breastfeeding practices that frequently accompany subsistence intensification. A fuller explanation of these fertility differentials, however, will require the collection of further high-quality microdemographic data from a variety of traditional societies.

Regional and geographical variations in infertility: effects of environmental, cultural, and socioeconomic factors.

Abstract: Fertility is affected by many different cultural, environmental, and socioeconomic factors, especially in developing countries where poverty and infections are commonplace. Environmental factors play a major role in infertility in Africa. One of the most important health problems in sub-Saharan Africa is the high rate of infertility and childlessness. The African society has a strong traditional heritage, and the study of the patterns of infertility in this part of the world would be incomplete without consideration of the sociocultural and environmental factors. The most cost-effective approach to solving the infertility problems in Africa is prevention and education. In Mexico, problems of reproductive health are associated with pregnancy in adolescents, sexually transmitted diseases and genitourinary neoplasms. Infertility affects 10% of couples, usually as a result of asymptomatic infection. Education, poverty, nutrition, and pollution are problems that must be tackled. The government has taken positive action in the State of Sao Paulo in Brazil, where gender discrimination is a major factor affecting women's health and reproductive outcomes. The implementation of new policies with adequate funding has resulted in marked improvements.

Life history costs and consequences of rapid reproductive maturation in female rhesus macaques

Abstract: Life history theory suggests that reproduction at one point in time involves costs in terms of energy, reduced survival, or probability of reproduction at a future point in time. ln long-lived iteroparous organisms, initiating reproduction at a relatively young age may exact a cost in terms of reduced survivorship, but an early age of first reproduction could be beneficial if it lengthens the breeding lifespan. Data collected over 30 years from one population of rhesus macaques, Macaca mulatta, were analyzed to determine the fertility and survivorship costs of initiating reproduction at a relatively young age. Low population density and high social status increased the chances of accelerating age at first parturition, but high dominance rank was not associated with greater lifetime reproductive success. Rapid reproductive maturation neither reduced short-term survivorship nor decreased lifespan. Fertility costs arose if young females reared a male, but not female, offspring. The fitness consequences of rapid reproductive maturation depend upon longevity, with age at death having a significantly greater impact on lifetime reproductive success than age at first parturition.

Consanguinity as a Determinant of Reproductive Behaviour and Mortality in Pakistan

Abstract: To determine the prevalence of consanguineous marriages and estimate the effects of consanguinity on reproductive behaviour and mortality, household and hospital-based surveys were conducted in 11 cities in the Pakistan province of Punjab between 1979 and 1985. The 9520 women interviewed reported 44474 pregnancies, with data collected on maternal and paternal ages at marriage, abortions/miscarriages, stillbirths and deaths in the first month, at 2–12 months and 2–8/10 years. Six categories of consanguineous marriage were included: double first cousin, first cousin, first cousin once removed/double second cousin, second cousin, bradari (brotherhood) and non-consanguineous. Marriages contracted between spouses related as second cousins or closer accounted for 50.3% of the total, equivalent to an average coefficient of kinship (α = σpiFi) of 0.0280. Unions between close biological relatives were characterized by younger maternal and paternal ages at marriage and reduced spousal age difference, but a longer time to first delivery. Overall, they exhibited greater fertility than non-consanguineous couples. Antenatal and postnatal mortality were assessed by consanguinity and age interval. Consanguinity-associated deaths were consistently higher in the neonatal, infant and childhood periods. The consequences of these outcomes on the health of the present and future generations is assessed.

Reproductive status of cheetahs (Acinonyx jubatus) in North American Zoos: The benefits of physiological surveys for strategic planning

Abstract: Under the mandate of a Species Survival Plan (SSP), reproductive status was assessed in 128 cheetahs maintained in 18 different institutions in North America. A mobile laboratory research team evaluated cheetahs using anesthesia, serial blood sampling, electroejaculation (males), and laparoscopy (females). Biomaterials were also collected for parallel studies of genetics, nutrition, and health. There was no mortality, and cheetahs were capable of reproducing naturally after these intense manipulatory examinations. No marked differences were observed in reproductive or endocrine characteristics between proven and unproven breeders. However, males consistently produced teratospermic ejaculates, and cheetah sperm were compromised in conspecific or heterologous in vitro fertilization systems. Structurally abnormal sperm were found to be filtered by the oocyte's zona pellucida. More than 80% of the females were anatomically sound, but morphological and endocrine evidence suggested that ∼50% or more of the population may have had inactive ovaries at the time of the examination. Males ranging in age from 15 to 182 months produced spermic ejaculates, but motile sperm numbers/ejaculate and circulating testosterone concentrations were highest in males 60 to 120 months old. Parovarian cysts were observed in 51.5% of female cheetahs, but comparisons between proven and unproven subpopulations revealed that this abnormality likely had no influence on fertility. Fresh luteal tissue was not observed in any nonpregnant or nonlactating female, strongly suggesting that the cheetah is an induced ovulator. Overall survey results were discussed in the context of the etiology of reproductive inefficiency, especially with respect to the potential importance of biological versus management factors. Four high priority research areas in cheetah reproductive biology were identified: 1) continuous monitoring of ejaculate quality in the extant population, while studying the impact of pleiomorphisms on fertility; 2) determining the potential relationship between libido and androgen production (excretion) in males; 3) confirming the extent of cyclic, or acyclic, ovarian activity in females; and 4) continued development of assisted reproductive techniques for enhancing man-agement. In summary, a multidisciplinary, multi-institutional survey coordinated through the SSP is both possible and useful for generating a physiological and health database beneficial to driving further research and management initiatives. © 1993 Wiley-Liss, Inc.

The fertility decline in developing countries

Abstract: The demographic transition in the more developed Western nations from high mortality and high fertility to low mortality and low fertility transpired gradually over many decades. Given that modern methods of contraception had yet to be invented educational levels were low and mass communication was limited most couples relied upon sexual abstinence withdrawal and/or abortion to limit fertility. These obstacles were eliminated over time and the desire for smaller families soon became deeply rooted throughout most Western countries. In recent years this desire has spread rapidly among women in the developing world. The trend cuts across cultural political social and economic lines. In fact the average rate of total fertility in developing countries has declined from 6 to 4 since the mid-1960s. This transition has occurred far faster than that observed in the more economically developed and industrialized countries and had taken place even in the absence of improved living conditions. While economic development and social change create supportive conditions in which fertility may decline the promotion and availability of modern contraceptive methods are the most important engines of change. Fertility has declined so rapidly in developing countries because of the existence and availability of modern contraceptive technologies growing levels of educational attainment mass media and the assistance of governments and donor agencies in developing and implementing family planning programs. The author discusses the demographic transitions of both developed and developing countries and stresses the need for the maintenance and expansion of family planning programs around the world.