SEARCH · PubMed Health
Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
Preselective sex determination in ten consecutive pregnancies has been achieved by means of strict control over timing and technique of coitus which was combined with acidic or alkaline douching. Eight female and two male babies were born.
The present study was undertaken to determine whether couples with one or more daughters and no sons had an increased probability of having a male child after using male sex preselection. The sex ratio of children born to couples after using 'protocol 3' (n = 70) or 'modified protocol 3' (n = 28) male sex preselection at one of 14 centres was determined. The normal approximation to the binomial distribution was used to determine significant differences between these sex ratios and the established sex ratio for children born to couples with one previous daughter and no sons. The sex ratios of both protocol 3 sex-preselected children (73.0%; P less than 0.0001) and modified protocol 3 sex-preselected children (86%; P less than 0.0001) were significantly different to the established sex ratio (control) for a current child born to parents with one previous daughter and no sons (50.1%). Couples with one or more daughters and no sons will have an increased probability of a male child after using male sex preselection.
The present study was undertaken to determine if couples with exclusively female children had a decreased probability of a male child after using male sex preselection. Selection criteria for subjects necessitated that couples have had only female children previously and had produced a child at one of 14 centers after using protocol 3 (n = 70) and modified 3 (n = 28) male sex preselection. Prior to sex selection, protocol 3 couples produced a combined total of 135 female children for an average of 2.01 (range 1-4) females per couple; modified 3 couples produced a combined total of 62 female children for an average of 2.21 (range 1-4) females per couple. The normal approximation to the binomial distribution was used to determine significant differences between the sex ratios prior to and after male sex preselection. For couples using protocol 3 there were significant differences in the sex ratio prior to sex preselection (0%) and after sex preselection (73.0%) (p less than .00003). There were also significant differences between the sex ratio prior to modified 3 (0%) and after sex preselection (86%) (p less than .00003). Couples using male sex preselection do not have a decreased probability of a male child if they have had exclusively female children.
A prospective study of sex preselection provided the opportunity to characterize the fertile menstrual cycle. We describe from 91 natural conceptual cycles, or sub-groups thereof, cervical mucus symptoms, basal body temperature (BBT) changes, hormonal characteristics, and the outcome of pregnancy. The cervical mucus symptoms defined a potential fertile period of 10 days' average length, with the "peak" mucus symptom occurring at a mean of day 15.5 of the cycle. A fertile period of 9 to 10 days was also indicated by pregnancies resulting from single acts of intercourse between -6 and +3 days from ovulation. The BBT chart was biphasic in 73 of 76 cycles. The duration of the LH surge as observed in early morning urine samples averaged five days, with the peak occurring 1.4 days after the onset. Considerable inter-subject variability was seen in the LH excretion levels. Hormone measurements of peripheral plasma during the luteal phase showed the first detectable presence of hCG between day 7 and day 13 after conception. Progesterone concentrations in the midluteal phase exceeded 20 nmol/L and tended to be higher than in a comparison group of nonfertile cycles, whereas the estradiol concentrations were similar in fertile and nonfertile cycles. The birth sex ratio favored males when intercourse preceded ovulation/fertilization by two days or longer. While this association was statistically significant, the number of pregnancies involved is too small to conclude that the relationship is real.
There have been attempts to select the sex of a child prior to conception in both animals and humans. Centrifugation, microelectrophoresis and density gradient sedimentation have been used to separate X and Y sperm in animals. Only the latter technic has produced a change in sex ratio. In the human, timing of coitus or artificial insemination in relation to ovulation has been the popular method for influencing the sex of a child. This review suggests caution in accepting the claims of success for coital timing. Sperm bearing the Y chromosome can now be identified by quinacrine staining. Using this marker, Ericsson showed that when sperm are allowed to swin into columns of liquid albumin a high percentage of Y-bearing sperm are found in the most distal portion of the column. At this time it has not been shown whether the fraction enriched with Y sperm can produce a preponderance of males.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Semen samples obtained from 18 normal males and 37 husbands requesting male child preselection were separated on concentration gradients of human serum albumin. Separated semen obtained from the husbands was then used for artificial homologous insemination (AIH). A significant increase in the sperm motility, progressive drive, and percentage of Y-bearing sperm along with a decrease in the total sperm count and percentage of abnormal forms were observed in separated specimens. Fathers of three or more female children had a slightly smaller but statistically significant percentage of Y-bearing sperm in their semen samples than did normal males. Ten conceptions were achieved with separated semen. Seven pregnancies terminated in normal deliveries of five male and two female infants, one ended in a spontaneous abortion of a male fetus, and two patients are still expecting. The ratio of male to female conceptions in this small study parallels the ratio of Y to X sperm in the final specimen used for AIH.
Explore the source record for details and available documents.
An outline of fetal antenatal sex determination and its diagnostic methods are rapidly enumerated. Actual methods are based on direct and indirect identification of sexual chromosomes from three types of cells : desquamated ones in amniotic fluid, fetal lymphocytes circulating in maternal blood and desquamated chorionic cells from endocervical smear. Three methods are utilizable : evidence of sexual chromatine, fluorescence specificity of the Y chromosome and the karyotype. Cells from amniotic fluid permit a correct prediction up to 97,5 p.100. However, the high risk of contamination limits its use. There is a 86 p. 100 diagnostic certainty with fetal lymphocytes in maternal blood or cervical desquamated chorionic cells. Future sex preselection may be contemplated and along with this the speculative social consequences. On the other hand, sex determination and volontary selection are limited at the moment by available technics and also by scientific and medical ethics.
Explore the source record for details and available documents.
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.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
A survey of 242 undergraduates assessed attitudes toward use of sex selection technology and the choice of sex of first- and second-born offspring among potential users. Of our sample, 31 per cent endorsed use of sex selection technology, with the small subsample of nonwhites more accepting of utilization than were whites. There was a significant preference for first-born sons among all potential users, but nonwhites indicated a stronger preference than did whites. Students from rural areas were more desirous of boys than were urban residents. The desire for gender balance within the family documented in earlier studies did not manifest itself. Choice of gender of second child was independent of preference for first-born, with 54 per cent of the potential users desiring sons as both first and second children.