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Year : 2019  |  Volume : 7  |  Issue : 1  |  Page : 30-34

Preconception sex determination: Maternal demographic variables as a predictive “tool”

1 Department of Human Anatomy, Kaduna State University, Kaduna, Nigeria
2 Department of Anatomy, College of Medicine, University of Lagos, Lagos, Nigeria
3 Department of Human Physiology, Kaduna State University, Kaduna, Nigeria

Date of Web Publication13-Sep-2019

Correspondence Address:
Dr. Timothy Danboyi
Department of Human Physiology, Kaduna State University, Kaduna
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/njecp.njecp_20_19

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Background: The unending attempt targeted at having a particular sex has led to unplanned increase in family sizes, especially in the developing world. Most published studies on sex selection did not consider the effects of maternal variables. Objective: The main objective of the study is to investigate the effects of maternal variables: age, date of the last menstrual period (LMP), blood group, and genotype on the sex of a baby. Materials and Methods: One hundred and twenty-seven case files of women who attended the Antenatal and Postnatal Clinics at the Lagos University Teaching Hospital, Idi-Araba, Lagos, between 2013 and 2015 were randomly selected. They comprised women between the ages of 18 and 40 years. Data extracted were maternal age, LMP, blood groups, and genotypes of mothers and sexes of their babies. Results: The percentages of boy (38.4%) to girl (9%) child born to mothers with LMP occurring in 1st week (day 1–7) of the month were significant (P < 0.05) compared to 2nd, 3rd, and 4th week, with male-to-female percentages of 12.3%–25.9%, 15.1%–24.1%, and 34.3%–33.3% (P > 0.05), respectively. There was no association between genotype and blood groups of the mothers and the sex of the baby (P > 0.05). Conclusion: The study showed correlations between the sex of the infants and the week of the month of LMP supporting maternal involvement in sex determination.

Keywords: Determination, maternal, preconception, sex

How to cite this article:
Yama OE, Adeyemo IN, Kusemiju TO, Dosumu OO, Gbotolorun SC, Avidime OM, Danboyi T. Preconception sex determination: Maternal demographic variables as a predictive “tool”. Niger J Exp Clin Biosci 2019;7:30-4

How to cite this URL:
Yama OE, Adeyemo IN, Kusemiju TO, Dosumu OO, Gbotolorun SC, Avidime OM, Danboyi T. Preconception sex determination: Maternal demographic variables as a predictive “tool”. Niger J Exp Clin Biosci [serial online] 2019 [cited 2021 Oct 15];7:30-4. Available from: https://www.njecbonline.org/text.asp?2019/7/1/30/266837

  Introduction Top

The yearning of couples all over the World is to select the preferred sex of their unborn babies; this desire has hugely gone unfulfilled repeatedly meeting a “brick wall” despite various researches in the field of reproductive science. Sex selection is any technique or intervention intended to increase the likelihood of the conception of a child of a particular sex.[1] The essential crux of this technique is the fact that it is actually a preconception method that allows the ability to predict the sex of an unborn child prior to its formation. Hence, a proper understanding of the key correlated features associated in human reproductive biology is, therefore, germane. This transcends the “sacred” conventional complicated preimplantation genetic diagnosis using in vitro fertilization method which is fundamentally a postconception technique involving taking a cell from each embryo 3 days after fertilization, and analyzing the DNA and chromosomes. Only the embryos of the desired sex are subsequently planted. It is currently the only 100% scientifically guaranteed way of choosing the sex of a baby.[2],[3] Although this method, apart from being invasive, costly and time-consuming, it has raised several ethical and legal concerns in various countries.[4]

There are other sundry gender or sex selection theories which are barely supported by scientific evidence but are however widely believed to have “enjoyed” previous successes in selecting the gender of a baby. Most till date stands as mere folkloric assertions, “old wives” tales, or myths and are yet to be scientifically verified often raised medical questions. Shettles' method of sex selection [5] is based on the premise that the Y-chromosome-carrying sperm is faster, smaller, and die quicker than the X-chromosome-carrying sperm. Research has shown that the ovule controls its electrical charge in an irregular but alternating predictable pattern so as to attract either X-bearing chromosomes at one time or Y-bearing chromosomes at another.[6],[7] This phenomenon, called the “cyclic variation of ovule polarity,” is fixed for each species and specific to each one. The “even and odd number myth” using basal body temperature as a predictive guide to the recording date of ovulation, its value is added to the date of the 1st day of last menstrual period (LMP) plus the age of the mother. Odd number means a male gender while even number female. The Chinese gender chart which requires the Chinese age on certain date to be calculated followed by Chinese lunar calendar conversion and finally pregnancy and baby gender chart using the Chinese lunar calendar.[8]

Quality of life arguments have been advanced as reasons for sex selection as is said to enhance the quality of life more for a child of the wanted sex and provide the better quality of life for the family that has the balance it desires. It is expected to reduce untoward tension and likelihood of downsizing family as a consequence of an unending attempt at getting a particular sex.[9],[10] It provides a better quality of life for the mother, because she will undergo fewer births to have the desired number of children of each sex.[10]

This present study critically examines the association between the sex of a baby and routinely documented antenatal maternal variables such as date of the LMP, age, blood group, and genotype and how this could predict the sex of the baby before conception. It excludes other factors such as, time of the day of sexual intercourse, type of food consumed, and weight/body mass of the mother.

  Materials and Methods Top

Ethical clearance

Approval for the study was sought and obtained from Lagos University Teaching Hospital (LUTH) Health Research and Ethics Committee; LUTHREC Registration Number: 19/12/2008a.

Study population

The retrospective study was carried out between July and September 2015 at the Department of Anatomy, College of Medicine University of Lagos. It was conducted on the antenatal and postnatal files of patients that attended the antenatal care/postnatal care clinic of LUTH within 3 years (2013–2015). One hundred and twenty-seven case files were randomly selected. They comprised women between the ages of 18 and 40 years. Data were extracted manually, recorded on study forms, and entered into a computerized database. The sex of the neonate, including other variables, was carefully reviewed and extracted from their medical records irrespective of the mode of delivery. The study, however, excluded women with multiple gestations, congenital malformation to avoid ambiguities in the interpretations of findings.

Data collection

In detail, the extracted information from the case files included the following parameters: (i) maternal age, (ii) the date of the LMP, (iii) blood group, (iv) genotype, and (v) the sex of baby.

Statistical analysis

Data entry and analysis were carried out using Statistical Package for the Social Sciences version 20.0 (IBM Corporation, New York, United States). Categorical variables were summarized using percentage, while numerical variables were summarized using mean ± standard deviation. The test of association of the child and other categorical variables were carried out using Pearson's Chi-square. Fisher exact test was used as the test of association where Chi-square was not valid. The numerical variables (the clinical parameters) were compared between male and female using independent sample t-test. Simple and multiple logistic regressions (multivariable analysis) of the presence of male sex were carried out on the associated factors. Values at P < 0.05 were considered significant.

  Results Top

The data were obtained from the medical records of 127 patients [Table 1]. Only mothers with normal singleton deliveries either via spontaneous vaginal or cesarean section were included. The sexes of the neonate were male: 73 (57%) and female: 54 (43%). The highest percentages of male sex child were from mothers under the ages of 18 years.
Table 1: Age of mother and the sex of infant

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The proportion of women that had their LMP occurring between the months of January and June had a total of seven (11.1%) babies delivered, of which 5.6% were male and 5.5% female [Table 2]. While those within the months of July–December had a total of 120, of which 69 (94.6%) were male and 51 (94.4%) female. These values of sex distribution throughout the year from the monthly LMP distribution were not statistically significant (P > 0.05). However, the association became statistically significant (P < 0.05) in mothers whose LMP occurred in the 1st week of the month when the relation of the day of LMP was compared to sex of baby delivered. The percentages of boy child were 38.4% as against 9% girl child born to mothers with LMP that occurred in the 1st week (day 1–7) of the month. For days 8–14, 15–21 and 22–31, the male-to-female percentages were 12.3%–25.9%, 15.1%–24.1%, and 34.3%–33.3%, respectively.
Table 2: The month and day of last menstrual period and sex of the infant

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There was no statistically significant association between genotype and blood groups of the mothers and the sex of the baby, (P > 0.05) [Table 3].
Table 3: Correlation between maternal blood group, genotype, and the sex of the infant

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Conception in the 1st week of the month resulted in increased incidence of male conception for all the maternal age groups, while in the 2nd and 3rd week, there were more girls conceived for early and late twenties and thirties [Table 4]. The 4th week showed higher conception of male infants in the teenage and early twenties mothers and higher rate of female infants conception for the older age groups.
Table 4: Extrapolated possible outcome of pregnancies on last menstrual period and age of the mother

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  Discussion Top

As science has progressed, accurate gender prediction methods have become greatly sort after, although there are still many myths showing up around the idea of predicting baby genders. Reproductive scientist hitherto held the view that the sex of a child is a matter of chance and depended on whether an X or Y chromosome bearing spermatozoa fertilizes the ovum. Much work concentrated on the problems of identifying and separating X- and Y-chromosome bearing spermatozoa.[11],[12] However, the last three decades, scientists have provided consistently significant evidence supporting maternal involvement in the predetermination of the sex of a baby.[13]

The preliminary findings in this present study showed a strong association between the sex of the infant and the week of the month of maternal LMP. Although it was discovered that the tendency to have male children were significantly higher for younger cohort mothers (group of >20 years), most mothers whose LMP occurred in the 1st week of the month delivered baby boy irrespective of their ages. In the 2nd and 3rd week, the percentage tendency for female was higher than male conceptus, although values not statistically significant (P > 0.05). In the 4th-week LMP mothers, the percentages were almost equal for both sexes with mothers in the teenage and early twenties showing higher conception of male infants and higher rate of female conceptus in mothers in older age groups. This means that infant gender outcome for male was stronger when the mean LMP occurs in 1st and 4th weeks and female sex when it occurs in the 2nd and 3rd week. The reason for this finding is unknown and is subject to further investigation but may not be unconnected with possible increases in calorie intake of mothers during this period that may have favored the conception of male offspring. It is important to note that it is within this period wages are paid to workers in this part of the World and the choice of calorie consumption expected to increase. The caption “you are what your mother eats” aptly comes to bear and captures the correlation between diet and the sex of the infant.[14] Previous studies give credence to this fact, in which it was shown that increased calories had linear effects on the sex of infant.[15] In work, it was shown that the higher calorie intake mothers were more likely to conceive a male child. Mothers with increased male offspring per 20 births were shown to consume more calories (2200) calories, compared to low intake group with fewer than 1850 calories.[15] The research also showed a decline in the male sex of babies born to mothers in developed countries, where many young women chose to have low-calorie diets.

The blood type theory postulates that a couple with A or B blood group is likely to have a girl; however, spouses with AB or O types will conceive a boy with Rh factor playing significant role. If both couples are negative or positive, the sex of the baby would probably be a girl.[16] Findings in this present study documented only the maternal genotype and blood group, which showed no significant correlation with the sex of the baby.

The strong link between the sex of the baby, maternal age, and the week of the month their date of last menses falls is mirrored as decreased chances of having a male child with the older mothers, while the younger mothers more likely to have male child. The implication of this is that a simple preliminary birth chart could be deduced, as shown in [Table 4] for predicting and selecting the baby of desired sex. Like the Chinese chat which dates back to the 13th century for predicting sex claims more than 95% success rate.[8]

Other maternal factors are currently being investigated as described in earlier studies and folkloric assertions in predicting the sex of the unborn baby. These include variations in the uterine environment, the date (timing) of fertilization,[17],[18] and cyclic variations in ovule polarity to either accept X- or Y-chromosome-bearing spermatozoa [7],[19],[20] as well as the immunohistochemical markers on the zona pellucida in the menstrual phases.

  Conclusion Top

This study provided a pilot guide into insights into the sex of a baby before conception for prospective couples planning for their future families.


We appreciate the contributions of the management and staff of the Lagos University Teaching Hospital, Lagos Nigeria.

Financial support and sponsorship

This research received a grant from the Central Research Committee of the University of Lagos, Lagos State, Nigeria.

Conflicts of interest

There are no conflicts of interest.

  References Top

Human Fertilization and Embryology Authority Document on Sex Selection. Available from: http://www.sexualhealthmatters.com. [Last accessed on 2011 Mar 23].  Back to cited text no. 1
Sex selection and preimplantation genetic diagnosis. The ethics committee of the American society of reproductive medicine. Fertil Steril 1999;72:595-8.  Back to cited text no. 2
Kathy H. Genetic testing of human embryos: Ethical challenges and policy choices. In: Galston A, Peppard C, editors. Expanding Horizons in Bioethics. Springer: Dordrecht, The Netherlands. p. 103-22.  Back to cited text no. 3
Eftekhaari TE, Nejatizadeh AA, Rajaei M, Soleimanian S, Fallahi S, Ghaffarzadegan R, et al. Ethical considerations in sex selection. J Educ Health Promot 2015;4:32.  Back to cited text no. 4
Shettles L, Rorvick DM, Rodeck CH. How to Choose the Sex of Your Baby: The Method Best Supported by Scientific Evidence. New York: Random House; 2006. p. 1.  Back to cited text no. 5
Carter H. Pick the sex test. Herald Sun (Melbourne); 1999.  Back to cited text no. 6
Baby by Gender. Following Natures' Way Boy or Girl? The Choice is Yours; 2013. Available from: http://www.babybygender.com/newsite/Product_Information/Scientific_Review.asp. [Last accessed on 2015 May 22].  Back to cited text no. 7
Ashley SA. Pregnancy Story: gender Myths and Predictions. Available from: http://www.ashleysisk.com/2012/02/a-pregnancy-story-gender-myths-and-predictions.html. [Last accessed on 2012 Jan 20].  Back to cited text no. 8
Sex Selection and Family Balancing. Available from: http://www.fertility; docs.com/fertility_gender.phtml?gclid=CJfo9Py9sLgCFaTItAod5mIAPg. [Last accessed on 2013 Jan 04].  Back to cited text no. 9
Wertz DC, Fletcher JC. Fatal knowledge? Prenatal diagnosis and sex selection. Hastings Cent Rep 1989;19:21-7.  Back to cited text no. 10
Beernink FJ, Dmowski WP, Ericsson RJ. Sex preselection through albumin separation of sperm. Fertil Steril 1993;59:382-6.  Back to cited text no. 11
Prakash MA, Kumaresan A, Manimaran A, Joshi RK, Layek SS, Mohanty TK, et al. Sexing of spermatozoa in farm animals: A mini review. Adv Animal Vet Sci 2014;2:226-32.  Back to cited text no. 12
Grant VJ, Chamley LW. Can mammalian mothers influence the sex of their offspring peri-conceptually? Reproduction 2010;140:425-33.  Back to cited text no. 13
Allison A. Can a Pregnant Woman's Diet affect Baby's Sex? Available from: http://www.npr.org/templates/story/story.php?storyid=99346281. [Last accessed on 2009 Jan 15, 12:56 am].  Back to cited text no. 14
Mathews F, Johnson PJ, Neil A. You are what your mother eats: Evidence for maternal preconception diet influencing foetal sex in humans. Proc Biol Sci 2008;275:1661-8.  Back to cited text no. 15
Baby Gender Prediction by Parents' Blood Types; 2016. Available from: http://whatsmybabygender.com/parents-blood-types#sthash. 8hbMhmMU.dpuf. [Last accessed on 2017 Dec 02].  Back to cited text no. 16
Wilcox AJ, Weinberg CR, Baird DD. Timing of sexual intercourse in relation to ovulation. Effects on the probability of conception, survival of the pregnancy, and sex of the baby. N Engl J Med 1995;333:1517-21.  Back to cited text no. 17
Gray RH. Natural family planning and sex selection: Fact or fiction? Am J Obstet Gynecol 1991;165:1982-4.  Back to cited text no. 18
Saling PM. How the egg regulates sperm function during gamete interaction: Facts and fantasies. Biol Reprod 1991;44:246-51.  Back to cited text no. 19
Mittwoch U. Sex differentiation in mammals and tempo of growth: Probabilities vs. switches. J Theor Biol 1989;137:445-55.  Back to cited text no. 20


  [Table 1], [Table 2], [Table 3], [Table 4]


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