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\"The ninth edition of Taking Sides: Clashing views in Gender contains 40 dynamic points of view, separated into 20 challenging, often contentious questions. There is also an \"Is there common ground?\" section at the end of each issue, which explores whether there is room for compromise on some or all of these controversial topics.\"--Preface.

This article examines the recent rise in the sex ratio at birth in Vietnam and relates its emergence to kinship systems and ethnic composition using 2009 census micro-data. Presentation of the main socioeconomic and ethnic differentials in birth masculinity is followed by a review of the three intermediate factors leading to increases in the sex ratio at birth: prenatal technology, declining fertility, and gender bias. An indirect measurement of fertility behavior is used to demonstrate the close association between levels of the sex ratio at birth and the intensity of son preference. Data on household composition indicate that Vietnam is characterized by the co-existence of kinship patterns typical of East and Southeast Asia. Son preference in Vietnam is found to be related to the prevalence of more traditional patrilineal systems. The article concludes by considering the implications of the cultural dimensions of prenatal sex selection for policy responses and for the likely future change in the sex ratio at birth.

Fertilization with sex-sorted semen is the most used approach to increase the proportion of female calves in dairy farms; however, it is commonly characterized by a lower pregnancy rate. We provide new insights into embryo developmental morphokinetics following fertilization with sorted semen. We also examined whether morphokinetic parameters are sex specific and can be used to select embryos with a desired sex. The first experiment included in vitro fertilization with X- and Y-sorted or unsorted semen. Embryos were developed in a time-lapse system and their developmental morphokinetics was recorded; blastocysts were collected for DNA-PCR and their sex was determined by TSPY and BOV97M expression. In the second experiment, fertilization was performed with unsorted semen and the embryo sex was predicted by the differential kinetic parameters that were found in the first experiment. The proportion of embryos that developed to blastocysts was higher in the unsorted vs. the sex-sorted group; embryos in this group also had diverse morphokinetics. Moreover, male and female embryos displayed different developmental kinetics. The prediction rate for male embryos was relatively low (~ 59–67%), indicating a limited accuracy of sex predication based on the kinetic data. A larger-scale study with a higher number of embryos might clarify this point.

This review presents information on biochemical features of spermatozoa bearing X or Y chromosome, enabling production of a sperm fraction with pre-defined sex chromosome. The almost only technology currently used for such separation (called sexing) is based on the fluorescence-activated cell sorting of sperm depending on DNA content. In addition to the applied aspects, this technology made it possible to analyze properties of the isolated populations of spermatozoa bearing X or Y chromosome. In recent years, existence of the differences between these populations at the transcriptome and proteome level have been reported in a number of studies. It is noteworthy that these differences are primarily related to the energy metabolism and flagellar structural proteins. New methods of sperm enrichment with X or Y chromosome cells are based on the differences in motility between the spermatozoa with different sex chromosomes. Sperm sexing is a part of the widespread protocol of artificial insemination of cows with cryopreserved semen, it allows to increase proportion of the offspring with the required sex. In addition, advances in the separation of X and Y spermatozoa may allow this approach to be applied in clinical practice to avoid sex-linked diseases.

We document male-biased sex ratios among U.S.-born children of Chinese, Korean, and Asian Indian parents in the 2000 U.S. Census. This male bias is particularly evident for third children: If there was no previous son, sons outnumbered daughters by 50%. By contrast, the sex ratios of eldest and younger children with an older brother were both within the range of the biologically normal, as were White offspring sex ratios (irrespective of the elder siblings' sex). We interpret the found deviation in favor of sons to be evidence of sex selection, most likely at the prenatal stage.

The use of sexed semen in dairy and beef farms ensures the production of animals of the desired sex, resulting in a reduction of costs and an improvement of environmental sustainability. Several methods have been developed over the years, but most of them were abandoned due to their limited efficacy. Currently, the only commercially available method for the separation of X- and Y-chromosome-bearing sperm is fluorescence-activated cell sorting. However, this technique is expensive and has limited usefulness for the industry, considering that it cannot produce doses of sexed semen with the desired number of sperm for artificial insemination. Immunological methods have emerged as an attractive alternative to flow cytometry and proteomic knowledge of X- and Y-sperm could be useful to the development of a new method. In this review, we identify the main applications of sexed semen, describe the existing methods and highlight future research opportunities in the field. We consider that immunological methods, based on sperm cell's surface proteins differentially expressed between X- and Y-sperm, could be an interesting and promising approach to semen sexing.

Widespread commercial application of sexed semen is expected within the next decade because of continued improvements in fertility of sexed semen and sorting capacity. The objective of this study was to explore the potential impact of widespread application of sexed semen on the structure of the dairy industry in the United States. Historically, female offspring from all heifers and cows were needed to produce enough dairy replacement heifers to replace culled cows. The use of sexed semen allows for a decoupling of breeding decisions necessary to obtain an adequate supply of dairy replacement heifers from those needed to achieve pregnancies needed to start new lactations. Application of sexed semen allows dairy producers to select among their herds’ potential dams and produce dairy replacement heifers from only the genetically superior animals. The rate of genetic progress is expected to increase, but not more than 15% of the rate of gain accomplished through sire selection achieved through conventional (nonsexed) artificial insemination breeding. The supply of dairy replacement heifers is expected to grow to meet and temporarily exceed current demand, resulting in reduced prices for dairy replacement heifers. Consequently, herd turnover rates are expected to increase slightly, and herd expansions may accelerate. The rate of consolidation of dairy farms is expected to increase. Widespread application of sexed semen may temporarily increase the supply of milk, which would result in lower milk prices. The cost of milk production will be reduced as well. Many breeding options exist for the genetically poorer cows in the herd. The optimal breeding mix depends on the value of the various kinds of calves that could be produced. More crossbred calves for beef production may be produced; however, a market for these crossbred calves is not well established. Increased specialization is expected with more dairy producers deciding not to raise their own heifers but to purchase replacements. Other dairy farms might specialize in producing genetically superior dairy replacement heifers for sale. Depending on the value of calves not raised for replacements, artificial insemination organizations might market beef conventional semen or beef male sexed semen to dairy farms. The use of sexed semen should lower the cost of progeny-testing programs and embryo transfer and enhance the value of genetic markers. Eventually, the economic benefits from the use of sexed semen will be passed on to consumers.

We present a micro-founded simulation model that formalizes the \"ready, willing, and able\" framework, originally used to explain historical fertility decline, to the practice of prenatal sex selection. The model generates sex ratio at birth (SRB) distortions from the bottom up and attempts to quantify plausible levels, trends, and interactions of son preference, technology diffusion, and fertility decline that underpin SRB trajectories at the macro level. Calibrating our model for South Korea, we show how even as the proportion with a preference for sons was declining, SRB distortions emerged due to rapid diffusion of prenatal sex determination technology combined with small but growing propensities to abort at low birth parities. Simulations reveal that relatively low levels of son preference (about 20 % to 30 % wanting one son) can result in skewed SRB levels if technology diffuses early and steadily, and if fertility falls rapidly to encourage sex-selective abortion at low parities. Model sensitivity analysis highlights how the shape of sex ratio trajectories is particularly sensitive to the timing and speed of prenatal sex-determination technology diffusion. The maximum SRB levels reached in a population are influenced by how the readiness to abort rises as a function of the fertility decline.

To what extent should parents be allowed to use selection technologies (such as preimplantation genetic diagnosis) to determine the characteristics of their children? And is there something morally wrong with parents who wish to do this? Choosing Tomorrow's Children provides answers to these questions. In particular, the book applies the techniques of philosophical bioethics to address issues raised by selective reproduction, the practice of choosing between different possible future persons by selecting or deselecting (for example) embryos, eggs, and sperm. It offers answers to questions including the following. Do children have a ‘right to an open future’ and, if they do, what moral constraints does this place upon selective reproduction? Under what circumstances (if any) should sex selection be allowed? Should we ‘screen out’ as much disease and disability as possible before birth, or would that be an objectionable form of eugenics? Is it acceptable to create or select a future person (a ‘saviour sibling’) in order to provide life-saving tissue for an existing relative? Is there a moral difference between selecting to avoid disease and selecting to produce an ‘enhanced’ child? And should we allow deaf parents to use reproductive technologies to ensure that they have a deaf child? The book does not provide one overarching conclusion but rather assesses each argument-type on its merits. Insofar as it is possible to generalise though, Choosing Tomorrow's Children concludes that most of the arguments usually provided against selective reproduction are flawed in one way or another.