Hormona antimülleriana como marcador de respuesta ovárica en pacientes tratadas por fertilización in vitro / Anti-Müllerian hormone as a marker of ovarian response in patients treated with in vitro fertilization

Introducción: La infertilidad afecta al 15 por ciento de las parejas en edad fértil, de las que aproximadamente 4-8 por ciento requerirán técnicas de reproducción asistida de alta tecnología. Con la incorporación de la mujer a la vida laboral y la consiguiente postergación de la maternidad es posible el aumento de la infertilidad. La hormona antimülleriana en la mujer se produce por las células de la granulosa. Esta regula el reclutamiento de folículos, su crecimiento y previene el agotamiento folicular, por lo que constituye una importante herramienta en los protocolos de inducción de la ovulación. Objetivo: Evaluar los niveles de la hormona antimülleriana como marcador de respuesta ovárica en pacientes tratadas por fertilización in vitro. Método: Se realizó un estudio descriptivo, observacional y de corte transversal en la consulta protocolizada de Reproducción Asistida del Hospital Clínico Quirúrgico Hermanos Ameijeiras, en el periodo comprendido de abril 2017 hasta abril 2019. La muestra quedó conformada por 137 mujeres que participaron en esta consulta. Se empleó estadística descriptiva e inferencial. Resultados: La edad promedio de las pacientes fue de 33,1 ± 7,4 años. Predominó la concentración sérica normal de la hormona antimülleriana en mujeres entre 31-35 años (26,3 por ciento), nivel normal de FSH en (39,4 por ciento), recuento de folículos antrales normal (24,1 por ciento), buena calidad ovocitaria (39,4 por ciento), y buena calidad embrionaria (36,5 por ciento). Conclusiones: El nivel sérico de la hormona antimülleriana se asoció significativamente a la edad, la hormona folículo estimulante, el recuento de los folículos antrales, y la calidad ovocitaria y embrionaria(AU)

Introduction: Infertility affects to 15 percent of the couples in childbearing age, and approximately 4-8 percent of them will need high-tech assisted reproduction techniques. With the participation of women in work life and the subsequent delay of maternity, it is possible the increase of infertility. Anti-Müllerian in women is produced by granular cells. These cells control the recruitment of follicles, their growth and prevent follicles exhaustion; therefore, it represents an important tool in the protocols of ovulation induction. Objective: Assess the levels of anti-Müllerian hormone as a marker in the ovarian response in patients treated with in vitro fertilization. Methods: It was conducted a descriptive, observational and cross-sectional study in the consultation of Assisted Reproduction in "Hermanos Ameijeiras" Surgical Clinical Hospital, in the period April, 2017 - April, 2019. The sample was formed by 137 women who attended to this consultation. It was used descriptive and inferential statistics. Results: Average age of the patients was 33,1 ± 7,4 years old. There was predominance of normal serum concentration of anti-Müllerian hormone in women among 31-35 years old (26,3 percent), FSH normal level in (39,4 percent), normal recount of antral follicles (24,1 percent), good oocyte quality (39,4 percent), and good embryonic quality (36,5 percent). Conclusions: The serum level of the anti-Müllerian hormone was significantly associated to age, the follicle-stimulating hormone, the recount of antral follicles, and the oocyte and embryonic quality(AU)

Aislamiento de SARS-CoV-2 en tejido reproductor, una posible vía de transmisión / No disponible

No disponible

Fragmentación del ADN espermático en parejas tratadas por fertilización in vitro / Sperm DNA fragmentation in couplestreated by in vitro fertilization

RESUMEN Introducción: Se estudian los factores que afectan el ADN espermático en la actualidad y en qué medida influyen en la aplicación de las técnicas de reproducción asistida de alta tecnología. La fertilización in vitro es un tema de interés que ha motivado a muchos investigadores. Objetivo: Determinar la relación que existe entre el índice de fragmentación del ADN de la cromatina espermática y los resultados de la técnica de fertilización in vitro en parejas infértiles. Métodos: Se realizó un estudio descriptivo transversal en 107 parejas infértiles remitidas del Programa Nacional de Atención a la pareja infértil, donde se precisó la asociación entre el potencial fertilizante y las variables de resultados: tasa de fertilización, calidad embrionaria y embarazo. Se estudiaron, además, algunos factores que pueden influir en el grado de fragmentación del ADN. Resultados: El potencial fertilizante no se relacionó con la tasa de fertilización, ni con el embarazo clínico, pero sí con la calidad embrionaria (P= 0.036). La edad paterna resultó ser estadísticamente significativa en relación con el potencial fertilizante (P= 0.032). La presencia de varicocele se asoció con el bajo potencial fertilizante (OR= 5,27; IC 95 por ciento [1.34 - 24.09]). Conclusiones: El índice de fragmentación del ADN de la cromatina espermática afecta negativamente la calidad de los embriones a transferir. La edad y el varicocele se relacionan positivamente con el grado de fragmentación del ADN espermático. El consumo de alcohol, el hábito de fumar y la exposición a agentes físicos y químicos no se relacionaron con el índice de fragmentación del ADN espermático en este estudio(AU)

ABSTRACT Introduction: The factors that affect the spermatic DNA are being studied at present and in what extent they affect the implementation of high technology assisted reproduction techniques. In vitro fertilization is a topic of interest that has motivated many researchers. Objective: To determine the relationship between the rate of DNA fragmentation of sperm chromatin and the results of in vitro fertilization technique in infertile couples. Methods: A descriptive cross-sectional study was conducted in 107 infertile couples referred to the National Program of Attention to the Infertile Couple, where it was specified the association between the potential fertilizer and outcome variables: rate of fertilization, embryo quality and pregnancy. In addition, there were studied some factors that may influence the degree of DNA fragmentation. Results: The fertilizing potential was not related to the rate of fertilization, or with the clinical pregnancy, but it did with the embryo quality (p= 0.036). The paternal age proved to be statistically significant in relation to the fertilizing potential (p= 0.032). The presence of varicocele was associated with the low fertilizing potential (OR = 5.27; CI 95 percent [1.34 - 24.09]). Conclusions: The rate of DNA fragmentation of sperm chromatin negatively affects the quality of the embryos to be transferred. The age and varicocele are positively related with the degree of sperm DNA fragmentation. The consumption of alcohol, the smoking habit and the exposure to chemical and physical agents were not associated with the rate of sperm DNA fragmentation in this study(AU)

Acquired angioedema with anti-C1-inhibitor autoantibodies during assisted reproduction techniques

No disponible

Compromised oocyte quality and assisted reproduction contribute to sex-specific effects on offspring outcomes and epigenetic patterning.

Clinical studies have revealed an increased incidence of growth and genomic imprinting disorders in children conceived using assisted reproductive technologies (ARTs), and aberrant DNA methylation has been implicated. We propose that compromised oocyte quality associated with female infertility may make embryos more susceptible to the induction of epigenetic defects by ART. DNA methylation patterns in the preimplantation embryo are dependent on the oocyte-specific DNA methyltransferase 1o (DNMT1o), levels of which are decreased in mature oocytes of aging females. Here, we assessed the effects of maternal deficiency in DNMT1o (Dnmt1Δ1o/+) in combination with superovulation and embryo transfer on offspring DNA methylation and development. We demonstrated a significant increase in the rates of morphological abnormalities in offspring collected from Dnmt1Δ1o/+ females only when combined with ART. Together, maternal oocyte DNMT1o deficiency and ART resulted in an accentuation of placental imprinting defects and the induction of genome-wide DNA methylation alterations, which were exacerbated in the placenta compared to the embryo. Significant sex-specific trends were also apparent, with a preponderance of DNA hypomethylation in females. Among genic regions affected, a significant enrichment for neurodevelopmental pathways was observed. Taken together, our results demonstrate that oocyte DNMT1o-deficiency exacerbates genome-wide DNA methylation abnormalities induced by ART in a sex-specific manner and plays a role in mediating poor embryonic outcome.

Ethical issues in human reproduction: Protestant perspectives in the light of European Protestant and Reformed Churches.

Protestantism is not a centralized religion. It is composed by many independent Churches having different moral and ethical standards. This review concentrates on the ethical principles prevalent in most modern European Reformed Churches. It does not intend to discuss the ethical principles of many other Protestant Churches present mainly in the USA. The common foundations of Protestant theology are the "five sola ("Sola scriptura", Sola fide", "Sola gratia", Solus Christus or Solo Christo", "Soli deo gloria"). In opposition to the Catholic Church, no intermediary is needed between the Bible and the believer. As a consequence, Protestant Churches have no Magisterium, such as the Catholic Church. Therefore Protestant Churches cannot declare a certain position to be the "official position". Each Christian is personally responsible for all his acts, including his ethical behaviour. There is no complete unanimity among all Protestants on ethics or on any other issue. Human dignity, personal rights and self-determination have to be respected in each ethical consideration. The supersession of the Old Mosaic Covenant (including traditional Jewish law or Halakhah, maintained in Catholicism) by the New Covenant and by Christian Theology has an important impact on Protestant ethics in reproductive medicine. In the New Covenant, the Protestants Churches did not maintain the mandatory obligation from the old Mosaic Covenant to be fruitful and to multiply: there is no divine obligation by God to procreate. As a consequence, contraception is not a sin and not unethical. The status of the embryo is the key for the ethical consideration of all methods used in reproductive medicine. Most representatives of modern Protestant theology and bioethics defend the opinion that the embryo is not an independent human being as is the newborn child. For most Protestant bio-ethicists, as long as an embryo has no nervous system, no organs and no pain receptors, it cannot be seen as a human being sensu strictiori: the zygote is not yet a "human being". The ethical right to be protected prenatally increases gradually with the age and the development of the embryo. Following this so-called gradualist interpretation, the early stages of an embryo merit ethically a special status: although they have already "human life", they are not yet a "human being". All ethical considerations in modern reproductive medicine discussed in this review are based on this concept of the status of the embryo. It depends largely on the acceptance or rejection of this special status of the embryo, if a Protestant considers a certain method in reproductive medicine to be ethical or unethical.

Ethical issues in human reproduction: Catholic perspectives.

The catholic perspective in human reproduction is based on the concept that the human being is to be respected and treated as a person from the moment of conception. In this paper the ethical implications derived from such a principle are discussed.

Human reproduction: Jewish perspectives.

Developments in science and technology and corresponding clinical applications raise new religious questions, often without clear answers. The role of theology in bioethics is integral to clarify perceived attitudes toward these developments for different religious communities. The Jewish attitude towards procreation is derived from the first commandment of God to Adam to 'Be fruitful and multiply'. Judaism allows the practice of all techniques of assisted reproduction when the oocyte and spermatozoon originate from the wife and husband respectively. This paper presents the attitude of Jewish Law -- Halacha to therapeutic procedures, such as IVF-embryo transfer, spermatozoa, oocytes, embryo donation, cryopreservation of genetic material, surrogacy, posthumous reproduction, gender preselection, reproductive and therapeutic cloning.

Ethical issues in human reproduction: Islamic perspectives.

Sexual and reproductive rights of women are essential components of human rights. They should never be transferred, renounced or denied for any reason based on race, religion, origin, political opinion or economic conditions. Women have the right to the highest attainable standard of health care for all aspects of their reproductive and sexual health (RSH). The principle of autonomy emphasizes the important role of women in the decision-making. Choices of women in reproduction, after providing evidence based information, should be respected. Risks, benefits and alternatives should be clearly explained before they make their free informed consent. Justice requires that all be treated with equal standard and have equal access to their health needs without discrimination or coercion. When resources are limited there is tension between the principle of justice and utility. Islamic perspectives of bioethics are influenced by primary Sharia namely the Holy Quran, authenticated traditions and saying of the Profit Mohamed (PBUH), Igmaa and Kias (analogy). All the contemporary ethical principles are emphasized in Islamic Shariaa, thus these principles should be observed when providing reproductive and sexual health services for Muslim families or communities. The Family is the basic unit in Islam. Safe motherhood, family planning, and quality reproductive and sexual health information and services and assisted reproductive technology are all encouraged within the frame of marriage. While the Shiaa sect permits egg donation, and surrogacy the Sunni sect forbids a third party contribution to reproduction. Harmful practices in RSH as FGM, child marriage and adolescent pregnancy are prohibited in Islam. Conscientious objection to treatment should not refrain the physician from appropriate referral.

Development of bovine embryos derived from reproductive techniques.

Assisted reproduction techniques have improved agricultural breeding in the bovine. However, important development steps may differ from the situation in vivo and there is a high mortality rate during the first trimester of gestation. To better understand these events, we investigated the development of embryos and fetal membranes following fixed-time AI (FTAI), IVF and nuclear transfer (NT). The onset of yolk-sac development was not normal in cloned embryos. Later steps differed from conditions in vivo in all three groups; the yolk-sac was yellowish and juxtaposed with the amniotic membrane. Vascularisation of the chorioallantoic membrane was relatively late and low in NT gestations, but normal in the others. The overall development of the embryos was normal, as indicated by morphology and regression analysis of growth rate. However, NT conceptuses were significantly smaller, with the livers in some embryos occupying the abdominal cavity and others exhibiting heart abnormalities. In conclusion, the yolk-sac and the cardiovascular system seem to be vulnerable to morphogenetic alterations. Future studies will focus on gene expression and early vascularisation processes to investigate whether these changes may be responsible for the high incidence of intrauterine mortality, especially in clones.

Gestación multifetal yatrogénica / Iatrogenic multifetal pregnancy

Los embarazos múltiples ocurren de forma espontánea, en una de cada 90 gestaciones en el caso de las gemelares, y en una de cada 8.100 en las triples. Sin embargo, desde el desarrollo de las unidades de reproducción humana se ha identificado un incremento del 52% de gestaciones gemelares y del 404% en las de mayor orden. Ante la elevada morbimortalidad perinatal y materna de estos embarazos y con el fin de incrementar las posibilidades de supervivencia de los fetos resultantes y minimizar la morbilidad a largo plazo en los recién nacidos, surge la embriorreducción selectiva. A pesar de ser una técnica rentable, puede implicar compromisos éticos y es un procedimiento no exento de riesgos. Por todo esto, consideramos que la actitud más eficaz ante las gestaciones múltiples es su prevención primaria (AU)

Multiple pregnancies spontaneously occur in one out of 90 pregnancies for twins and in one out of 8,100 for triplets. However, since the introduction of human reproduction units, there has been a 52% increase in twins, and a 404% increase in high-order pregnancies. Given the high perinatal and maternal morbidity and mortality in these pregnancies, selective embryo reduction was developed to increase fetal survival and reduce long-term morbidity in neonates. Although effective, this procedure represents a technical and ethical challenge for the practitioner. Consequently, we believe that the most effective approach to multifetal pregnancies is primary prevention (AU)

Embarazo heterotópico diagnosticado en una cesárea a término / Gestational sack over a previous cesarean section scar: case report and review of the literature

El embarazo heterotópico está aumentando su incidencia como consecuencia del avance de las técnicas de reproducción asistida. Es importante realizar un diagnóstico precoz pues la rotura de la gestación ectópica puede llegar a ser una urgencia potencialmente mortal. Presentamos un atípico caso clínico en el que el diagnóstico de la gestación extrauterina se realizó en el transcurso de una cesárea electiva a término (AU)

We present the case of a pregnant woman with an 8-week history of amenorrhea and insertion of a gestational sac over a previous cesarean section scar. Methotrexate treatment was unsuccessful and laparotomy was performed. We provide a literature review and update on the incidence, diagnostic methods and current treatment options of this entity (AU)

Efectos de la selección y de la superovulación en las pérdidas gestacionales de ratonas CF1 / Effects of selection and superovulation on gestational losses in CF1 mice

En un par de líneas de ratones seleccionadas para alto (s') y bajo peso (s), originadas a partir de una población no seleccionada de la cepa CF1 (t), se modificó la estructura ovárica. El diámetro de los folículos ováricos y el número de folículos y de cuerpos lúteos se incrementaron en las hembras de la línea s', sin expresarse en un mayor tamaño de camada al nacimiento, posiblemente, por un aumento de las pérdidas gestacionales. Se probó si los efectos conjuntos de la selección de peso a largo plazo y de la estimulación ovárica incrementaban las pérdidas gestacionales. Se utilizaron dos grupos de hembras por línea: sin y con estimulación ovárica (5UI de eCG y 5UI de hCG). Las hembras se sacrificaron a las 56-72 hs y a los 7 días postservicio y después de la primera parición. Se observaron los números de cuerpos lúteos (CL), embriones (E) y sitios de implantación (SI) y el tamaño de camada al nacimiento (TC). Se estimaron las pérdidas totales (PT) y las pérdidas de cuerpos lúteos (PCL), de embriones (PE) y de fetos (PF). Los promedios de CL, E, SI y TC variaron en el mismo sentido de la selección practicada y fueron significativamente mayores (P<0,05) para las hembras estimuladas, a excepción de TC. La línea s' tuvo un potencial reproductivo superior pero un mayor costo biológico (mayor PT y más tardía) cuando se la comparó con las otras líneas. La estimulación ovárica produjo menores eficiencias reproductivas totales para las tres líneas y pérdidas gestacionales mayores y más tardías, principalmente de SI. Las hembras de la línea no seleccionada (t), no estimuladas, con pesos intermedios, parieron un mayor número de crías, partiendo de un número intermedio de CL, E y SI, con una menor y más temprana mortalidad embrionaria, demostrando ser las más eficientes desde el punto de vista reproductivo y productivo.

The ovarian structure was modified as a consequence of weight selection in a pair of mouse lines selected for high (s') and low weight (s). Lines were founded from an unselected population of CF1 strain (t). The follicle diameter and the number of the ovarian follicles and the corpora lutea were higher in s' females, but they did not reach a larger litter size at birth, may be, by an increase in the gestational losses. In these lines, the co-effects of long-term weight selection and ovarian stimulation were tested to evaluate if they increased gestational losses. Two groups of females per line were employed: without and with ovarian stimulation (5UI of eCG and 5UI of hCG). Females were slaughtered at 56-72hs and at 7 days post-breeding and after first parturition. The number of corpora lutea (CL), embryos (E) and implantation sites (SI), and litter size at birth (TC) were observed. Total losses (PT) and corpora lutea (PCL), embryo (PE) and fetus (PF) losses were estimated. Mean CL, E, SI and TC varied in the same direction of the selection made and they were significantly higher (P<0.05) in stimulated females, though not for TC. Line s' had a higher reproductive potential but a greater biological cost (higher and later gestational mortality) when compared with the other lines. Ovarian stimulation produced lower total reproductive efficiencies for the three lines and higher and later gestational losses, mainly for implantation sites. Females from unselected line (t), without ovarian stimulation, with intermediate weights, bore larger litters, starting from an intermediate number of CL, E and SI, with a lower and earlier embryo mortality, showing to be the most efficient from a reproductive and productive point of view.

Factores relacionados con las técnicas de reproducción asistida y su repercusión en el neonato / Factors associated with assisted reproduction technologies and neonatal outcomes

Introducción: Las técnicas de reproducción asistida (TRA) pueden estar asociadas a complicaciones obstétricas y perinatales, incluido un aumento de malformaciones. El objetivo de este estudio fue comparar los resultados obstétricos y neonatales de las gestaciones únicas y múltiples por fertilización in vitro (FIV) e ICSI (intra cytoplasmatic sperm injection`inyección intracitoplásmica de espermatozoides) con las gestaciones espontáneas. Pacientes y métodos: Estudio de casos y controles de los recién nacidos de embarazos obtenidos con las técnicas FIV e ICSI en el Hospital Clínic de Barcelona entre enero de 1999 y diciembre de 2005. Se recogieron 499 casos y 432 controles. Resultados: El grupo estudio (gestaciones por FIV e ICSI) tiene más prematuridad (definida como gestación inferior a 37 semanas), menor peso al nacer (definido como peso inferior al P10 para su edad gestacional y sexo), más embarazos múltiples, madres de mayor edad y más complicaciones obstétricas, como amenaza de aborto y prematuridad, enfermedad placentaria, hipertensión arterial, diabetes gestacional y hemorragias. Los recién nacidos muestran una enfermedad y una mortalidad similar con más ingresos. Al analizar sólo las gestaciones únicas, en el grupo estudio destaca más prematuridad y bajo peso al nacer, más complicaciones obstétricas, más enfermedades neonatales relacionadas con la prematuridad y el aumento de malformaciones (el 9,7 frente al 4,3%, respectivamente; p=0,046). Al analizar sólo las gestaciones múltiples no hay diferencia en prematuridad ni en peso al nacer, ni en número de malformaciones, pero el grupo estudio tiene más complicaciones obstétricas, como amenaza de aborto, diabetes gestacional y toxemia. Aunque la técnica ICSI tiende a asociarse a más malformaciones, no hay diferencia estadística significativa (el 11,0 frente al 5,6%, respectivamente; p=0,099) y el estudio multivariante no muestra una influencia independiente. Conclusiones: Las TRA (FIV e ICSI) se asocian con más prematuridad, bajo peso al nacer y aumento de enfermedad obstétrica. Las gestaciones únicas por FIV e ICSI muestran aumento de malformaciones si bien el riesgo de que éstas aparezcan no depende de las técnicas utilizadas (AU)

Introduction: Assisted reproduction technologies can be associated with poor obstetric and perinatal outcomes and an increase in congenital malformations. The objective of this study was to compare obstetric and perinatal outcome of single and multiple pregnancies conceived by IVF (in vitro fertilization) or ICSI (intracytoplasmic sperm injection) with spontaneous pregnancies. Patients and methods: A case-control study was conducted on the newborns conceived by IVF and ICSI in Hospital Clínic Barcelona between January 1999 and December 2005. There were 499 cases reported and 432 controls. Results: The case group had an increased risk of preterm birth (<37 weeks) and low birth weight (<10th percentile in relation to gestational age and sex). The case group had more multiple births, higher maternal age, more obstetric complications, such as abortion risk, preterm delivery, placental complications, hypertension, gestational diabetes, maternal haemorrhage. There were no significant differences in perinatal outcome, although newborn conceived by IFV/ICSI were admitted to hospital more. In single pregnancies, the case group showed more preterm deliveries and low birth weight, more obstetric complications and more congenital malformations (9.7% vs. 4.3% P=0.046). In multiple pregnancies there were no significant differences in perinatal outcome and incidence of malformations. The case group had a higher incidence of obstetric complications, such as abortion risk, gestational diabetes and hypertension. Although ICSI was associated to more malformations (11.0% vs. 5.6%), there was no significant statistical difference (P=0.099) and the multivariate analysis did not show an independent influence on risk of malformation. Conclusion: IFV/ICSI techniques have an increased risk of premature delivery, low birth weight, and poorer obstetric outcomes. Single pregnancies tend to have more congenital malformations. The risk of malformations is not associated with a specific technique (AU)

Understanding risks and benefits in research on reproductive genetic technologies.

Research protocols must have a reasonable balance of risks and anticipated benefits to be ethically and legally acceptable. This article explores three characteristics of research on reproductive genetic technologies that complicate the assessment of the risk-benefit ratio for such research. First, a number of different people may be affected by a research protocol, raising the question of who should be considered to be the subject of reproductive genetic research. Second, such research could involve a wide range of possible harms and benefits, making the evaluation and comparison of those harms and benefits a challenging task. Finally, the risk-benefit ratio for this type of research is difficult to estimate because such research can have unpredictable, long-term implications. The article aims to facilitate the assessment of risk-benefit ratios in research on reproductive genetic technologies by proposing and defending some guidelines for dealing with each of these complicating factors.

Is it ethically justifiable to cryopreserve oocytes and ovarian tissues of healthy women not facing premature ovarian failure, but seeking to extend their biological clocks?

Recent advances in oocyte and ovarian tissue cryopreservation technology have not only brought hope to women facing premature loss of ovarian function; it can also be utilized for healthy women seeking to extend their biological clocks. This is a major issue of contention in healthcare ethics. Proponents of this new technology argue that this enables women to fully pursue educational and career goals in their youth, whilst upon reaching middle age they would have more financial resources for their offspring. Nevertheless, this argument is flawed by the reality that even if the cryopreservation of oocytes and ovarian tissue were optimized, this would in no way be a guaranteed route for women to have biological children later in life. Moreover, because only a limited amount of autologous reproductive material can be cryopreserved and stored for a single healthy woman, there is a risk of material depletion before reproductive success is attained. Another prime consideration is the increased morbidity and mortality associated with clinical assisted reproduction in older women. Hence, it is suggested that the cryopreservation and storage of oocytes and ovarian tissues be restricted only to women facing the prospect of premature ovarian failure.

Guidelines for reducing the risk of viral transmission during fertility treatment.

These guidelines provide strategies, based on scientific principles and clinical experience, for reducing the risk of virus transmission in couples seeking treatment for infertility.

Application of sexed semen technology to in vitro embryo production in cattle.

Use of sexed semen in conjunction with in vitro embryo production is a potentially efficient means of obtaining offspring of predetermined sex. For thousands of years, livestock owners have desired a methodology to predetermine the sex of offspring for their herds. The ability to sort individual sperm cells into viable X- and Y-chromosome-bearing fractions made producers' sex selection dreams reality in the 1990s and now semen can be sexed with greater than 90% accuracy with use of a flow cytometric cell sorter. Several concerns regarding the implementation of sexed semen technology include the apparent lower fertility of sorted sperm, the lower survival of sorted sperm after cryopreservation and the reduced number of sperm that could be separated in a specified time period. These issues are discussed in this review. There are also a number of issues that appear to influence the success rates of using sexed semen to produce bovine embryos in vitro. These issues include reductions in fertilization rates, lower cleavage rates, blastocyst rates and pregnancy rates, partial capacitation of the sperm, dilute sperm samples and sire variation. These subjects are also addressed in this paper. Finally, we will describe a recent field trial in which female Holstein embryos produced using the combined technologies of sex-selected semen and microfluidics were transferred either as single or bilateral twin embryos into beef cattle recipients, demonstrating these technologies' contributions to viable embryo production. The results indicate that large-scale transfer of in vitro produced, Holstein heifer embryos to beef recipients is a feasible production scheme.