The Shettles Method for Sex Selection

A Closer Look at One Means of Sex Selection

Portrait of happy young family with baby boy (12-17 months).
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Sex selection is a huge topic in pregnancy and childbirth these days. One poll showed that only 17 percent of women did not have a preference for the sex of their babies. This desire to influence the process one way or the other has led to numerous theories on how to get pregnant with the girl or boy of one's dreams.

One such theory is the Shettles Method.

What Is the Shettles Method?

The Shettles Method has been around since the 1960s  and is named after the doctor who developed it: Landrum B.

Shettles. Shettles based his methods around the belief that the X and Y sperm are different from each other. He explored how people might be able to use these supposed differences to influence the sex of their baby.

There are numerous medical articles that examine why the Shettles Method is flawed, and most medical studies have not been able to replicate the numbers that Shettles himself claims to have seen. In fact, some studies have shown that those using the Shettles Method may actually have trouble conceiving.

The Facts

There are two types of sperm: X-bearing sperm and Y-bearing sperm. The egg, from the mother, is always an X. If an X-bearing sperm penetrates the egg, then the baby is a girl (XX). If the Y-bearing sperm penetrates the egg, then the baby is a boy (XY).

The Shettles Method Conjecture

Allegedly, certain things done during a woman's cycle or during intercourse can influence which of the sperm fertilizes the egg.

If you were using this method to try to conceive a girl, you would do things that favored the X-bearing sperm and, if you were trying to conceive a boy, you would do what supposedly influenced the Y-bearing sperm.

According to Shettles, X-bearing sperm survive longer in the cervical environment and are slower than their Y-bearing counterparts.

 Y-bearing sperm, on the other hand, are faster and smaller than their X-bearing counterparts, and are not as hearty and die more quickly.

So How Would One Using This Method Conceive a Girl or a Boy?

For one thing, if you were trying for a girl, you should have sex two to three days before ovulation in order to allow the Y-bearing sperm to die off before the egg became available during ovulation. Women would also avoid orgasms because it makes the vagina less favorable for the X-bearing sperm that prefer the acidic environment. You would also avoid sexual positions that involve deep penetration.

If you were trying for a boy, on the other hand, you would conversely use sexual positions with deep penetration, giving preference to the supposedly faster but less hearty Y-bearing sperm. You would have sex as close to ovulation as possible, to take advantage of the speed of the Y-bearing sperm. And women would try for those orgasms, preferably timing them to occur at the same time as their partner.

What Science Says About Shettles

In talking to families, it is never hard to find women who claim that Shettles Method worked for them. This anecdotal evidence, however, is not proof of its success.

Research conducted by other scientists tend to show that the Shettles Method does not work, and there is even some scientific evidence that says not only does it not work, but it can actually prevent you from getting pregnant.

In 1995, researchers in the New England Journal of Medicine proclaimed that "the timing of sexual intercourse in relation to ovulation has no bearing on the sex of the baby." There are similar studies in the International Journal of Fertility and the American Journal of Obstetrics and Gynecology.

Shettles did numerous studies himself and, not surprisingly, they were always positive.


According to research, there is no easy method of DIY sex selection.


France, J. T., F. M. Graham, et al. (1992). "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 37(4): 244-55.

France, J. T., F. M. Graham, et al. (1984). "A prospective study of the preselection of the sex of offspring by timing intercourse relative to ovulation. "Fertil Steril 41(6): 894-900.

Gray, R. H. (1991). "Natural family planning and sex selection: fact or fiction?" Am J Obstet Gynecol 165(6 Pt 2): 1982-4.

Shettles, LB. (1978). "Sex preselection." Obstet Gynecol. 1978 Apr;51(4):513-4.

Wilcox, A. J., C. R. Weinberg, et al. (1995). "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 333(23): 1517-21.