Female gender pre-selection by maternal diet in combination with timing of sexual intercourse – a prospective study

Published:September 01, 2010DOI:


      Natural sex selection methods have been applied for several decades, but their use and effectiveness are still a matter of debate. Therefore, this study assessed the efficacy of a maternal diet low in sodium and high in calcium, in combination with timing of intercourse well before ovulation as a method to improve the chances of conceiving a girl. A total of 172 couples wanting a girl participated in the study. For the 150 couples that actually started, compliance with diet was assessed through mineral analyses of blood and timing of intercourse relative to ovulation was determined by ovulation tests. Based on mineral blood values and timing of intercourse of 28 participants, a prediction rule for conceiving a girl was constructed and was tested prospectively for validity on a subsequent group of 50 women. In this group, 21 women satisfied the criteria of the prediction rule and 16 gave birth to a daughter. It is concluded that the combination of maternal diet with timing of intercourse is capable of increasing the probability of conceiving a girl (P = 0.005). The observed percentage of female babies for all 32 women satisfying the prediction rule was 81% (95% confidence interval 68–95%).
      Natural sex selection methods have been applied for several decades, but their use and effectiveness are still a matter of debate among medical professionals. Therefore, we assessed the efficacy of a maternal diet low in sodium and potassium, high in calcium and magnesium, in combination with timing of intercourse well before ovulation as a method to improve the chances of conceiving a girl baby. A total of 172 couples wanting a girl volunteered to participate in the study and the 150 couples that actually started were followed during their treatment and possible pregnancy. Compliance with diet was assessed through mineral analyses of blood. The participants determined timing of intercourse relative to ovulation by ovulation home tests. Based on mineral blood values and on the time interval between intercourse and ovulation, a prediction rule for conceiving a girl was constructed and tested for validity in a new group of 21 couples. In total, 32 women satisfied the conditions of the prediction rule and the observed percentage of female babies in this group was 81%. The conclusion of the study is that a maternal diet together with timing of sexual intercourse and use of a prediction rule will lead to an increased probability of a girl baby. It is important that both diet and timing are followed correctly, which requires of the mother both willpower and meticulousness.


      To read this article in full you will need to make a payment


        • Ben Porath Y.
        • Welch F.
        Do sex preferences really matter?.
        Quart. J. Econ. 1976; 90: 285-307
        • Berge-Landry H.V.
        • James G.D.
        Serum electrolyte, serum protein, serum fat and renal responses to a dietary sodium challenge: allostasis and allostatic load.
        Ann. Hum. Biol. 2004; 31: 477-487
        • Biggar R.J.
        • Wohlfahrt J.
        • Westergard T.
        • Melbye M.
        Sex ratios, family size, and birth order.
        Am. J. Epidemiol. 1999; 150: 957-962
        • Bolet G.L.
        • Guenguen P.
        • Dando P.
        • Ollivier L.
        Influence of mineral diet of the sow on the sex ratio of newborn.
        Reprod. Nutr. Dev. 1982; 22: 1073-1081
      1. The CIA World Factbook. <> (accessed 24.02.10).

        • Devaure N.
        • Dabadie H.
        • Paccalin J.
        Influence des apports nutritionnels dans le déterminisme du sexe.
        Diet. Med. 1989; 2: 155-163
      2. Duc, M., 1977. De l’influence des apport nutritionnels en ions K+, Na+, Ca2+, Mg2+ sur la sex-ratio chez l’homme. Ph.D. thesis, Université de Paris-Val-de-Marne, 56p.

        • France J.T.
        • Graham F.M.
        • Gosling L.
        • Hair P.
        • Knox B.S.
        Characteristics of natural conceptual cycles occurring in a prospective study of sex preselection: fertility awareness symptoms, hormone levels, sperm survival and pregnancy outcome.
        Int. J. Fertil. 1992; 37: 244-255
        • Fraser C.G.
        Biological Variation: From Principles to Practice.
        AACC Press, Washington, DC2001
        • Geraedts J.P.
        X spermatozoa larger than Y in 1973.
        Mol. Hum. Reprod. 1997; 3: 545-546
        • Gray R.H.
        • Simpson J.L.
        • Bitto A.C.
        • et al.
        Sex ratio associated with timing of insemination and length of the follicular phase in planned and unplanned pregnancies during use of natural family planning.
        Hum. Reprod. 1998; 13: 1397-1400
        • Grenache D.G.
        • Gronowski A.M.
        Reproductive testing: ovulation and pregnancy.
        in: Nichols J.H. Point of Care Testing: Performance Improvement and Evidence Based Outcomes. Marcel Dekker, Inc., New York, NY2003: 455-476
      3. Hardy I.C.W. Sex Ratios: Concepts and Research Methods. Cambridge University Press, 2002
        • Herbst C.
        Untersuchungen zur Bestimmung des Geschlechts: II. Die Abhängigheit des Geschlechts vom Kaliumgehalt des umgebenden Mediums bei Bonella viridis.
        Roux Arch. Ent. Org. 1935; 132: 578-599
        • Himmel W.
        • Michelmann H.W.
        Preconception sex selection: a survey of visitors to an internet-based health forum.
        Reprod. Biomed. Online. 2008; 16: 18-26
        • Hudson P.
        • Buckley R.
        Vegetarian diets: are they good for pregnant women and their babies?.
        Pract. Midwife. 2000; 3: 22-23
        • Jacobsen R.
        • Møller M.
        • Engholm G.
        Fertility rates in Denmark in relation to the sexes of preceding children in the family.
        Hum. Reprod. 1999; 14: 1127-1130
        • James W.H.
        The variations of human sex ratio at birth with time of conception within the cycle, coital rate around the time of conception, duration of time taken to achieve conception, and duration of gestation: a synthesis.
        J. Theor. Biol. 2008; 255: 199-204
        • Jeambrun P.
        Escolha pré-concepcional do sexo por meio de dieta.
        Servir. 1989; 38: 179-182
        • Karabinus D.S.
        Flow cytometric sorting of human sperm: MicroSort® clinical trial update.
        Theriogenology. 2009; 71: 74-79
        • Kleegman S.J.
        Can sex be predetermined by the physician?.
        in: Fifth World Congress of Fertility and Sterility, Stockholm, Sweden, June 16–22. 109. Excerpta Medica, 1966: 1185
        • Lorrain J.
        Pre-conceptional sex selection.
        Int. J. Gynecol. Obstet. 1975; 13: 127-130
        • Mangasarian O.L.
        Linear and nonlinear separation of patterns by linear programming.
        Oper. Res. 1965; 13: 444-452
        • Mathews F.
        • Johnson P.J.
        • Neil A.
        You are what your mother eats: evidence for maternal preconception diet influencing foetal sex in humans.
        Proc. R. Soc. B: Biol. Sci. 2008; 275: 1661-1668
        • McSweeney L.
        A prospective study of sex preselection in Ondo, Nigeria, using the Billings ovulation method of natural family planning.
        Bull. Nat. Fam. Plan. Counc. Victoria. 1993; 20: 9-16
        • Mortimer D.
        • Richardson D.W.
        Sex ratio of births resulting from artificial insemination.
        Br. J. Obstet. Gynaecol. 1982; 89: 132-135
        • Nybo Andersen A.M.
        • Wohlfahrt J.
        • Christensen P.
        • Olsen J.
        • Melbye M.
        Maternal age and fetal loss: population based register linkage study.
        Br. Med. J. 2000; 320: 1708-1712
        • Papa F.
        • Henrion R.
        • Breart G.
        Sélection pré-conceptionelle du sexe par la méthode ionique.
        J. Gynecol. Obstet. Biol. Reprod. (Paris). 1983; 12: 415-422
        • Sampson J.H.
        • Alexander N.J.
        • Fulgham D.L.
        • Burry K.A.
        Gender after artificial induction of ovulation and artificial insemination.
        Fertil. Steril. 1983; 40: 481-484
        • Shettles L.B.
        Factors influencing sex ratios.
        Int. J. Gynecol. Obstet. 1970; 8: 643-647
        • Sokal R.R.
        • Rohlf F.J.
        Biometry: The Principles and Practice of Statistics in Biological Research.
        third edition. Freeman, New York1994 (ISBN: 0-7167-2411-1)
        • Silverman A.Y.
        • Stephens S.R.
        • Drouin M.T.
        • Zack R.G.
        • Osborne J.
        • Ericsson S.A.
        Female sex selection using clomiphene citrate and albumin separation of human sperm.
        Hum. Reprod. 2002; 17: 1254-1256
        • Stolkowski J.
        Influence possible de la nutrition minérale sur la répartition des sexes chez la vache: une enquête rétrospective.
        C. R. Acad. Sci. D (Paris). 1967; 265: 1059-1062
        • Stolkowski J.
        • Choukroun J.
        Preconception selection of sex in man.
        Isr. J. Med. Sci. 1981; 17: 1061-1067
        • Stolkowski J.
        • Choukroun J.
        Sélection préconceptionnelle du sexe dans l’espèce humain par le déterminisme ionique.
        Rev. Fr. Endocrinol. Clin. Nutr. Metab. 1984; 25: 237-259
        • Stolkowski J.
        • Choukroun J.
        Diététique et sélection préconceptionnelle du sexe.
        Rev. Fr. Diet. 1986; 119: 4-9
        • Stolkowski J.
        • Lorrain J.
        Preconceptional selection of fetal sex.
        Int. J. Gynecol. Obstet. 1980; 18: 440-443
        • Vahidi A.R.
        • Sheikhha M.H.
        Comparing the effects of sodium and potassium diet with calcium and magnesium diet on sex ratio of rats’ offspring.
        Pak. J. Nutr. 2007; 6: 44-48
        • Westerterp K.R.
        • Goris A.H.C.
        Validity of assessment of dietary intake: problems of misreporting.
        Curr. Opin. Clin. Nutr. Metab. Care. 2002; 5: 489-493
        • Wilcox A.J.
        • Weinberg C.R.
        • Baird D.D.
        Timing of sexual intercourse in relation to ovulation.
        N. Engl. J. Med. 1995; 333: 1517-1521
        • Wyatt C.J.
        • Velázquez C.
        • Grijala I.
        • Valencia M.E.
        Dietary intake of sodium, potassium and blood pressure in lacto-ovo-vegetarians.
        Nutr. Res. 1995; 15: 819-830