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PubMed2004

Low dose insemination in the mare: an update.

The generally recommended minimum number of spermatozoa required for conventional artificial insemination in the mare is in excess of 200 x 10(6) progressively motile spermatozoa. Recent developments in different insemination techniques such as deep uterine, hysteroscopic and oviductal insemination, which have been designed to use significantly fewer spermatozoa, are reviewed in this paper. A number of studies have demonstrated that ultrasound guided deep uterine insemination of 5 x 10(6) fresh spermatozoa can produce satisfactory pregnancy rates. The use of hysteroscopic insemination enables the insemination dose to be successfully reduced to 1 x 10(6) fresh or 3 x 10(6) frozen-thawed spermatozoa. Further reduction of the insemination dose is possible and satisfactory pregnancy rates can also be achieved by surgical oviductal insemination of mares with as few as 2 x 10(5) fresh spermatozoa. The refinement of these insemination techniques will allow us to maximise the use of frozen-thawed semen, use new technology such as sex-preselection of spermatozoa and to conserve and utilise epididymal spermatozoa at the time of castration or death of a stallion.

Animals↗
PubMed2006

Millions of missing girls: from fetal sexing to high technology sex selection in India.

The morality and acceptability of using prenatal diagnosis for sex selection is being extensively debated around the world as advances in assisted reproductive technologies (ART) and embryology have enabled selective implantation of embryos of the desired sex (George and Dahiya, 1998; Savulescu, 1999; Raphael, 2002; Harris, 2005; Robertson, 2005; Snider, 2005). Sophisticated methods of separation of semen, originally developed for cattle breeding, are being used for human sex selection. Recently, non-invasive methods of fetal sex determination in the first trimester (from 6 weeks) of pregnancy have also emerged (Hahn and Chitty, 2005). Market forces that promote sex selection along with libertarian ideologues have assisted in blurring the ethical limits (Paul, 2001; President's Council on Bioethics, 2003). The widespread misuse of sex selection for eliminating girls before birth in India and among the Indian diaspora needs to be brought into the global 'intellectual discourse'. It is imperative that Western ethicists recognize the genocidal nature of sex selection taking place in certain Asian countries. Even if they believe that these trends will not affect mainstream Western societies, the promotion or tolerance of sex selection amounts to a 'crime of silence' against this ongoing genocide in China and India. I have been concerned with issues of the girl child in India for over two decades and sex selection among Asian Indians in North America (George et al., 1992; George et al., 1993; George and Dahiya, 1998). This article examines the missing millions of girls, but will not consider the 1980s campaign against fetal sex determination, Indian feminists' recognition of sex selection as violence against women (unlike several Western feminists, Moazam, 2004), or the Government's response to regulate prenatal diagnostic techniques in 1994 (George and Dahiya, 1998; George, 2002).

Abortion, Induced↗
PubMed1994

Gene-culture coevolution and sex ratios: the effects of infanticide, sex-selective abortion, sex selection, and sex-biased parental investment on the evolution of sex ratios.

The evolutionary consequences of culturally transmitted practices that cause differential mortality between the sexes, thereby distorting the sex ratio (e.g., female infanticide and sex-selective abortion), are explored using dynamic models of gene-culture coevolution. We investigate how a preference for the sex of offspring may affect the selection of genes distorting the primary sex ratio. Sex-dependent differences in mortality have been predicted to select for a male- or female-biased primary sex ratio, to have no effect, or to favor either under different circumstances. We find that when a mating pair's behavior modifies mortality rates in favor of one sex, but does not change the number of offspring produced in the mating, the primary sex ratio will evolve a bias against the favored sex. However, when the total number of offspring of a mating pair is significantly reduced as a consequence of their prejudice, the primary sex ratio will evolve to favor the preferred sex. These results hold irrespective of whether the sex ratio is distorted by the mother's, the father's or the individual's own autosomal genes. The use of dynamic models of gene-culture coevolution allows us to explore the evolution of alleles which distort the sex ratio, as well as the final equilibrium states of the system. Gene-culture interactions can provide equilibria different from those in purely genetic systems, slow the approach to these equilibria by orders of magnitude, and move the primary (PSR) and the adult sex ratio (ASR) away from any stable equilibrium for hundreds of generations.

Abortion, Induced↗
PubMed2005

Sex selection: laissez faire or family balancing?

In a recent comment on the HFEA's public consultation on sex selection, Soren Holm claimed that proponents of family balancing are committed to embrace a laissez faire approach. Given that arguments in support of sex selection for family balancing also support sex selection for other social reasons, advocates of family balancing, he asserts, are simply inconsistent when calling for a limit on access to sex selection. In this paper, I argue that proponents of family balancing are in no way inconsistent. Provided their advocacy of family balancing is aimed at preventing a severe distortion of the natural sex ratio, they are entirely justified in insisting on restrictions to sex selection. The real question is whether a concern for the sex ratio does indeed call for a limit on sex selection. Based on a recent survey on gender preferences and data from several Gender Clinics, I argue that a restriction on sex selection to family balancing is unwarranted. In the absence of any evidence for a pending sex ratio distortion, we are actually required to adopt a laissez faire approach to sex selection.

Bioethical Issues↗
PubMed2006

Social sex selection and the balance of the sexes: empirical evidence from Germany, the UK, and the US.

Preconception sex selection for nonmedical reasons is one of the most controversial issues in bioethics today. The most powerful objection to social sex selection is based on the assumption that it may severely distort the natural sex ratio and lead to a socially disruptive imbalance of the sexes. Based on representative social surveys conducted in Germany, the United Kingdom, and the United States, this paper argues that the fear of an impending sex ratio distortion is unfounded. Given the predominant preference for a "gender balanced family," a widely available service for social sex selection is highly unlikely to upset the balance of the sexes in Western societies.

Adult↗
PubMed1984

H-Y antigen and immunity: a means for controlling the secondary sex ratio?

C57BL/6J female mice were splenectomized and then sensitized to the H-Y antigen by means of grafts of H-Y incompatible skin and injections of spleen cells from syngeneic males. When subsequently mated to syngeneic males the secondary sex ratio of progeny born was significantly greater than that of controls. However, the effect was manifest only among the progeny of later litters (i.e., 3, 4, 5) suggesting that repeated exposure to the H-Y antigen during the course of pregnancy was essential to bring about demonstrable immunoregulatory changes.

Animals↗
PubMed2005

Sex allocation and interactions between relatives in the bean beetle, Callosobruchus maculatus.

When a small number of females contribute offspring to a discrete mating group, sex allocation (Local Mate Competition: LMC) theory predicts that females should bias their offspring sex ratio towards daughters, which avoids the fitness costs of their sons competing with each other. Conversely, when a large number of females contribute offspring to a patch, they are expected to invest equally in sons and daughters. Furthermore, sex ratios of species that regularly experience variable foundress numbers are closer to those predicted by LMC theory than species that encounter less variable foundress number scenarios. Due to their patterns of resource use, female Callosobruchus maculatus are likely to experience a broad range of foundress number scenarios. We carried out three experiments to test whether female C. maculatus adjust their sex ratios in response to foundress number and two other indicators of LMC: ovipositing on pre-parasitised patches and ovipositing with sisters. We did not find any evidence of the predicted sex ratio adjustment, but we did find evidence of kin biased behaviour.

Animals↗
PubMed2006

Preconception sex selection demand and preferences in the United States.

OBJECTIVE: Preconception sex selection for nonmedical reasons raises important moral, legal, and social issues. The main concern is based upon the assumption that a widely available service for sex selection will lead to a socially disruptive imbalance of the sexes. For a severe sex ratio distortion to occur, however, at least two conditions have to be met. First, there must be a significant preference for children of a particular sex, and second, there must be a considerable interest in employing sex selection technology. Our objective was to ascertain such demand and preferences among the United States general population. DESIGN: Cross-sectional web-based survey. SETTING: United States general population. PATIENT(S): One thousand one hundred ninety-seven men and women aged 18 to 45 years. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): Web-based questionnaire assessing preferences for sex of children and demand for preconception sex selection for nonmedical reasons. RESULT(S): Eight percent of respondents would use preconception sex selection technology, 74% were opposed, and 18% were undecided. If the sex selection process was simplified to taking a pill, 18% would be willing to use such a medication, 59% were opposed, and 22% were undecided. In terms of gender choices, 39% of respondents would like their first child to be a son, 19% would like their first child to be a daughter, and 42% had no preference. Overall, 50% wished to have a family with an equal number of boys and girls, 7% with more boys than girls, 6% with more girls than boys, 5% with only boys, 4% with only girls, and 27% had no preference. CONCLUSION(S): Preconception sex selection technology via sperm separation is unlikely to be used by the majority of the United States population and is unlikely to have a significant impact on the natural sex ratio.

Choice Behavior↗
PubMed2005

Seeking conception: experiences of urban Indian women with in vitro fertilisation.

OBJECTIVES: This paper reports on a study of involuntarily childless Indian women/couples seeking in vitro fertilisation (IVF). The focus is on the social context of infertility and on women's perceptions of and experiences with IVF. METHODS: Twenty-two childless women/couples who sought IVF. The sample was drawn from consenting clients of clinics in two major Indian cities, viz. New Delhi and Mumbai. RESULT: In-depth interviews revealed that infertility is deeply feared, women's status and security are affected, and they experience stigmatisation and isolation. IVF was pursued after less intrusive avenues had been exhausted. Inadequate information/counselling is provided, success rates are low, IVF is commercialised and the process is physiologically, emotionally and financially stressful. CONCLUSION: In Indian society fertility defines womanhood and motherhood, and infertility is stigmatised. Women faced a lot of pressures to produce a biological child, and go through all kinds of treatments, including the expensive ARTs, to have a child. PRACTICE IMPLICATIONS: Integration of infertility services into the state's reproductive health programme and disseminate information on infertility and to offer other appropriate choices, such as adoption. Effective counselling on coping with psychosocial/sexual problems. Monitoring of the prevalence of sex preselection.

Adaptation, Psychological↗
PubMed2006

Embryo production from superovulated sheep inseminated with sex-sorted ram spermatozoa.

An experiment was undertaken to assess the fertilizing capacity of sex-sorted, frozen-thawed ram spermatozoa, artificially inseminated into superovulated ewes, and the quality and survivability of the resultant pre-sexed embryos. Synchronized (intravaginal progestagen pessary and GnRH) donors were superovulated using PMSG and repeat ovarian stimulation with FSH before insemination. Ewes (n=67) were inseminated with either 30x10(6) or 15x10(6) motile non-sorted (control) or 15x10(6) motile sex-sorted (sorted) frozen-thawed spermatozoa (control: C30 or C15; sorted: S15, respectively) and the resultant embryos transferred immediately into synchronized recipients (n=160). The percentage of transferable embryos, pregnancy rate and embryo survival were similar (P>0.05) across all treatments. Oocyte cleavage rate was higher for ewes inseminated with S15 (172/230; 74.8%; P<0.05) than for C15 (97/151; 64.2%) or C30 (89/141; 63.1%) spermatozoa. Of the lambs resulting from embryos produced with sex-sorted spermatozoa, 86/93 (92.5%) were born of the predicted sex. This study demonstrated for the first time that pre-sexed offspring derived from superovulated sheep can be produced following transfer of embryos. Furthermore, sex-sorting by flow cytometry did not compromise the in vivo fertilizing capacity of ram spermatozoa in superovulated sheep, nor did it affect the quality or survivability of the resultant embryos.

Animals↗
PubMed1976

The effects of altering the pH of seminal fluid on the sex ratio of rabbit offspring.

It has been suggested that the pH of the vagina at the time of fertilization may have a differential effect on X- or Y-bearing sperm and thereby affect the sex of the offspring. To test this postulate, rabbit semen was collected, diluted 1:10 with a buffer of pH 5.4, 6.9, or 9.6, and after 20 minutes 0.5 ml of semen-buffer mixture was used for insemination in an ovulation-induced female. Newborn pups were examined both externally and internally for gender. The females inseminated with acidic semen had 6 litters, 50 offspring, with 48% males; those with neutral semen had 8 litters, 48 offspring, with 63% males; and those with alkaline semen had 7 litters, 49 offspring, with 49% males. There was no significant difference in these sex ratios from the expected 50% males. Motility of rabbit sperm at 23 degrees C in buffers of pH 4.6, 5.4, 6.9, 9.6, and 9.8 was reduced in vitro as the pH deviated from neutrality. Acid conditions were more detrimental than alkaline conditions. Sperm lost their motility more quickly in buffers of 37 degrees C than in buffers of 23 degrees C. It was not possible with scanning electron microscopy to distinguish morphologically between X- and Y-bearing sperm. It seems unlikely that a direct effect of pH on sperm can be a single influence on the sex of offspring.

Animals↗