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PubMedDate not supplied

[Methods of natural and voluntary sex selection. Value for the prevention of sex-linked malformations and of certain recurrent abortions].

Voluntary selection of the sex of a foetus may have an undeniable value in the prevention of certain diseases of malformations which are sex-linked. An indirect statistical control of the efficiency of these methods was carried out on 100 sterile treated couples. These couples agreed to respect a certain number of parameters which constitute the methods of voluntary selection of the sex of the foetus. Under these conditons and taking care that we were dealing only with cases where the sperm cell count was normal, the results were positive in 77%. It is probable the the results would have been above 80% if the parameter of the low pH of the vagina had been used as well. Attention was then directed to the possibility of using these methods to prevent certain sex-linked congenital malformations on the one hand (a classical idea) and prevention of certain repeated abortions on the other hand (a less well accepted idea). Three characteristic case histories have been reported to support these hypotheses.

Abortion, Spontaneous↗
PubMed1999

A controlled study for gender selection using swim-up separation.

OBJECTIVE: To evaluate the success for gender selection using a sample of semen separated by a modified swim-up technique. DESIGN: We retrospectively compared the gender outcome of two treatments (A and B) for either a male or female offspring with those who conceived spontaneously. SETTING: Private practice of one author (M. A.K.). PATIENTS, PARTICIPANTS: The treatment groups consisted of 52 total pregnancies for couples who conceived by the separation technique. Of these 52 participants, 15 desired a female offspring and were placed into treatment A and 37 desired a male offspring and were placed into treatment B. The control groups consisted of 162 women who were presented with initial consultation for gender selection and conceived spontaneously. Control group A consisted of 80 women who initially chose a female offspring, and control group B consisted of 82 participants who initially chose a male. INTERVENTIONS: In treatment group A, one timed intrauterine insemination (IUI) was carried out with the bottom 0.5 ml of the separated semen on cycle days 12-14, when the follicle was 18-22 mm. Patients in this group were also administered clomiphene citrate and human chorionic gonadotropin. In treatment group B, one timed IUI was done with the top 0.5 ml of the separated semen, when the follicle was 18-22 mm. MAIN OUTCOME MEASURE: The gender outcome of the pregnancies of two treatment and control groups was evaluated based on the known desired gender. RESULTS: The success rate for conceiving a female child after intervention (treatment group A) was 86.7% effective (p = 0.002) as compared to the control group A. Couples seeking a male child (treatment group B) were 89.2% effective (p = 0.0002) as compared to the control group B. CONCLUSIONS: This study reveals that the modified swim-up method with additional monitoring results in statistically significant gender preselection.

Adult↗
PubMed1998

Experiences in Hong Kong with the theory and practice of the albumin column method of sperm separation for sex selection.

Controversy still surrounds the human serum albumin (HSA) method for separation of X- and Y-bearing human spermatozoa. There is doubt about whether the procedure does enrich sperm samples for the chosen sex chromosome. We have applied the HSA separation method in a clinic in Hong Kong, using the method as described by Ericsson et al. [Nature, 246, 421-424 (1973)] taking care to keep the sperm recovery to <5% of the initial number. Aliquots of separated spermatozoa were examined for X- and Y-bearing spermatozoa by fluorescent in-situ hybridization (FISH) using appropriate DNA probes. Of 18 couples wanting boys, 13 had single boys, one had twin boys, and one had twins comprising one boy and one girl. Only three single girls were born. This success rate of 83% is significantly different (P < 0.001) from the usual expected ratio. There were four miscarriages, one in the third and one in the fourth week of pregnancy. The times of the others are not definitely known, but are thought to have occurred early in pregnancy. We lack information on three couples. The FISH procedure showed no change in the normal and equal numbers of X- and Y-bearing spermatozoa after the HSA separation procedure. This study confirmed that the HSA sperm separation method can bias the number of babies in favour of males. However, the theory that it does so by enriching the sperm samples with Y-bearing spermatozoa appears to be incorrect and some other theory has to be postulated. It is tentatively proposed that passage through the HSA inactivates X-bearing spermatozoa more than Y-bearing spermatozoa, even though this is not apparent simply on inspection of sperm motility.

Cell Separation↗
PubMed1997

Advances in gender preselection in swine.

Gender preselection using isolated populations of X- and Y-chromosome bearing spermatozoa that have been separated on the basis of DNA content is currently possible in swine and other farm animals, as well as in humans. Semen from most livestock species can now be successfully separated into predominantly X or Y sperm populations before their use for intra-tubal insemination, deep-uterine insemination or for in vitro fertilization (IVF) to produce sexed offspring. Birth of progeny of the desired sex in cattle, sheep and swine under semi-practical conditions has successfully validated the sexing technology. Spermatozoa are separated on the basis of inherent differences in DNA content in the X- and Y-chromosome bearing sperm population using modified flow cytometry/cell sorting technology. Spermatozoa are stained with Hoechst 33342 which binds to the DNA in an amount proportional to the amount of DNA present in the individual spermatozoa. Over 300 animals from various species at several locations have been born using the USDA-Beltsville Sperm Sexing Technology for separating X and Y spermatozoa. Sex ratios are shifted from the normal 50:50 to 85 to 90% of one sex or the other. In swine, offspring have been born as the result of surgical intratubal insemination of separated spermatozoa and also from IVF and embryo transfer. At the present time, standard swine artificial insemination techniques are not optimized for use with the small numbers of flow cytometrically separated X or Y sperm populations. Cattle, swine and rabbit offspring have been reproduced through the second generation with normal morphology and reproductive function. Numerous improvements have been made in the sexing technology since it was first reported in 1989. Increasing the speed of the sexing process to make the application of the technology available to a larger segment of the livestock industry is paramount, even with insemination technology designed for small numbers of spermatozoa.

Animals↗
PubMed1993

Flow cytometric analysis for reproductive biology.

Flow cytometric studies of spermatogenesis have been advanced by the need for: i) rapid, sensitive, objective and multiparameter measurements of reproductive effects due to environmental, occupational, and therapeutic exposure to toxicants; and ii) assessment of fertility potential of human and animal sperm. As a consequence, various flow cytometric techniques are already available to identify germ cell subpopulations undergoing both proliferative and maturative processes in normal and perturbed conditions. Significant improvements have been introduced in order to investigate the spermatogenic complex differentiation pathway and the apparent uniformity of mature sperm. Flow cytometry (FCM) has been applied to the measurement of both testis and sperm cells in a variety of species, including man. End points considered in toxicology studies are: altered testicular germ cell ratios, DNA and RNA content, increase of the coefficient of variation, induction of diploid elongated spermatids and diploid sperm, altered nuclear morphology, sperm cell viability, mitochondrial function and sperm chromatin structure. Precise DNA content measurements allow accurate analysis to determine the proportion of X- and Y-chromosome bearing sperm and sorting of these subpopulations for gender preselection. FCM technology has reached a maturation level that allows its inclusion in the list of available and routine methods for reproductive studies in human and animal populations.

Animal Husbandry↗
PubMed1991

Natural family planning and sex selection: fact or fiction?

Determining sex of offspring by timing of intercourse has been a subject of intense interest for the lay public and professional community. This metaaanalysis of couples practicing natural family planning provides an opportunity to evaluate sex ratios in relation to the timing of conception with several parameters, including basal body temperature shift and peak mucus as markers of ovulation. Data from six studies show a statistically significant lower proportion of male births among conceptions that occur during the most fertile time of the cycle.

Body Temperature↗
PubMed1993

Gender preselection in humans? Flow cytometric separation of X and Y spermatozoa for the prevention of X-linked diseases.

Human X- and Y-chromosome-bearing spermatozoa were separated based on their DNA content, using modified flow cytometric cell sorting technology. The resulting separation purity of the X-bearing from Y-bearing spermatozoa was evaluated using in-situ hybridization with alpha satellite DNA probes for the X- and Y-chromosomes. In the putative X-enriched-sorted populations, an average of 82% of the spermatozoa showed a hybridization signal with the X probe. Similarly, in the Y-sorted population 75% gave a signal with the Y probe. Sorted X- and Y-bearing spermatozoa were found to maintain their viability for several hours after sorting. These results demonstrate that the human sperm sex ratio can be significantly shifted to favour the selection of female-producing (X) spermatozoa or male-producing (Y) spermatozoa when spermatozoa are flow cytometrically sorted on the basis of DNA content. We propose that flow cytometrically sorted human spermatozoa, used in conjunction with in-vitro fertilization or intra-oviductal insemination, could be used by families who are at risk for X-linked diseases to preferentially produce female offspring. Sorted spermatozoa could also be used to pre-select for male offspring if that were medically indicated.

Cell Separation↗
PubMed1998

Birth of piglets preselected for gender following in vitro fertilization of in vitro matured pig oocytes by X and Y chromosome bearing spermatozoa sorted by high speed flow cytometry.

The present study examined the ability to establish pregnancies after transfer of pig embryos derived from in vitro fertilization (IVF) of in vitro matured (IVM) oocytes by X and Y chromosome-bearing spermatozoa sorted by flow cytometry. Cumulus-oocyte complexes (COC) were cultured in BSA-free NCSU-23 medium containing porcine follicular fluid (10%), cysteine (0.1 mg/mL), epidermal growth factor (10 ng/mL), LH (0.5 microgram/mL) and FSH (0.5 microgram/mL) for 22 h, then the oocytes were cultured without hormonal supplements for an additional 22 h. Boar semen was collected and prepared by flow cytometry sorting of X and Y chromosome bearing spermatozoa. After IVM, cumulus-free oocytes were co-incubated with sorted X or Y spermatozoa (2 x 10(4)/mL) for 6 to 7 h in modified Tris-buffered medium containing 2.5 mM caffeine and 0.4% BSA. After IVF, putative embryos were transferred to NCSU-23 medium containing 0.4% BSA for culture. A portion of the oocytes was fixed 12 h after IVF, the remainder were cultured up to 96 h. At 96 h after IVF, 8-cell to morula stage embryos (n = 30 to 35) from each gender were surgically transferred to the uterus of recipient gilts. Insemination of IVM pig oocytes with X- or Y-bearing sperm cells did not influence the rate of penetration (67 vs 80%), polyspermy (40 vs 53%), male pronuclear formation (95 vs 96%), or mean number of spermatozoa per oocyte (1.6 vs 1.6), respectively. Furthermore, no difference was observed between cleavage rates at 48 h after IVF (X, 49 vs Y, 45%). Transfer of embryos derived from X-bearing spermatozoa to 18 recipients resulted in 5 pregnancies and delivery of 23 females and 1 male piglet. Similarly, transfer of embryos derived from Y-bearing sperm cells to 10 recipients resulted in 3 pregnancies, with 9 male piglets delivered. The results show that X- and Y-bearing spermatozoa sorted using USDA sperm sexing technology can be successfully used in an IVM-IVF system to obtain piglets of a predetermined sex.

Animals↗