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Results for “Sex Preselection”

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At least 199 records · Page 11Linked to original sources
PubMed1988

How large should my study be so that I can detect an altered sex ratio?

The world literature on manipulations purported to alter the gender of offspring is a quagmire full of reports presenting inadequate data and contradictory conclusions. Many are due to inappropriate statistical design or analysis. The authors present simple, nontechnical reference tables for determination of the minimum sample size necessary to detect a change in sex ratio (1) from a theoretical value, and (2) between two experimental populations. Simple methods for analyzing the results of gender manipulation experiments are described. Technical details are included in a separate section.

Female↗
PubMed1987

Preconceptional sex selection.

The desire to control the sex of our offspring prior to conception has been present throughout man's history. In recent years the application of a more scientific approach to the problem has resulted in techniques capable of providing interested couples with an 80% chance of having either a boy or a girl according to their wishes. The medical, ethical, economic and sociological implications of these advances will require close attention in future years.

Diet↗
PubMed1983

[Preconceptional selection of sex using the ionic method. Dietary regime. Results of a 2 years' prospective clinical study].

45 women out of a total of 58 patients who followed a dietary regime appropriate to the sex they had chosen for their babies were successful in delivering a baby of the wanted sex. This result gives a success figure of 77.6% (the mean between 67 and 89%: p less than 0.001) and from the statistical point of view this difference is significant as compared with the natural sex ratio. The diets were overall well tolerated and the children at birth weighed normal weights. The parents seemed to request approximately equal numbers of girls as of boys--a balanced request. A high number of patients abandoned the method (75%). This is explained by the restrictions that are imposed by the diets and because the method would still appear to be experimental. It does seem that the ability to influence the sex ratio of the future offspring is possible when the ionic balance of the diet is changed. The study should be continued.

Clinical Trials as Topic↗
PubMed1983

A two-generation study of human sex-ratio variation.

We report here the first vertical population study of human sex-ratio variation. Sex-ratio data for 2 generations from Akita, Japan, have been analyzed. Parental age, birth order, sequences of the sexes at birth, and generations have no statistically significant effect on sex ratio. There is a slight excess of males at birth, as is typical for human sex-ratio studies. There is evidence of sex-ratio-dependent family planning. An analysis of vertical transmission of sex-ratio modifying factors that excludes effects of birth order in both the parental and offspring generations has detected a marginally significant paternal effect. Genetic variability of the sex ratio, if present at all, is of a very minor magnitude.

Adult↗
PubMed1981

Preconception selection of sex in man.

The determination of sex is influenced by ionic factors. In man, ionic imbalance is responsible for the sex ratio in at least 80% of cases, the possible mechanism being one of selective fertilization. These facts constitute the scientific basis for the medicodietary method of selecting sex. The intervention of ions in ovarian metabolism is obtained by controlling the diet of the woman, the decisive factor being the ratio of K+ + Na+ to Ca2+ + Mg2+ in the daily diet. High values of this ratio lead to boys, and low values to girls. Using this method since 1970 in 47 births, only 7 of them failed to produce the expected sex. The interactions and the causes of failure are analyzed.

Animals↗
PubMed1994

Five decades of missing females in China.

This paper seeks to explain the dearth of females in the population of China in cohorts born from the late 1930s to the present. We demonstrate that in virtually all cohorts, the shortage of females in comparison with males is revealed when the cohort is first enumerated in a census. Subsequently it barely changes, an indication that female losses occur very early in life. Using the high-quality data from the censuses and fertility surveys in China, we show that many of the births of the girls missing in the censuses were not reported in the surveys because they died very young. The incidence of excess early female mortality (probably infanticide) declined precipitously in the Communist period, but not to zero. The recent escalation in the proportion of young females missing in China has been caused largely by rapidly escalating sex-selective abortion.

Abortion, Legal↗
PubMed1995

X- and Y-chromosome-bearing sperm selection and detection methods. A review.

The ability to preselect the sex of human offspring would have a significant impact on the preventing of sex chromosome-linked diseases and on human reproduction. Numerous methods have been reviewed including: Sephadex gel filtration, centrifugation in density gradients, separation in albumin gradient, laminar flow, counterstreaming centrifugation, free-flow electrophoresis, galvanic method, two-phase system separation, flow cytometry, immunological exclusion. None of these methods seems to be ideal. Results obtained with the use of the most of them are contradictory, the others still need reliable confirmation. Part of the controversy related to the efficacy of methods aimed at sex selection may be due to the lack of appropriate and widely used techniques of X- and Y-chromosome bearing sperm detection. Fluorescent in situ hybridization appears to be the most suitable among the sperm sex chromosome detection techniques described in this review. Others, like quinacrine staining method, human sperm/hamster oocyte penetration assay, microinterferometry, cytometry, and polymerase chain reaction exhibit more or less disadvantageous features, which limit their application.

Cell Separation↗