Gender Selection

Imagine this conversation between a husband and wife:

Husband: "Honey, I think it's time we started trying."

Wife (innocently): "Trying for what, sweetie?"

H: "Um,… a baby?"

W: "Are you sure?"

H: "Well, what about you?"

W: "I am if you are."

H: "Wow, that's great. I love you. But, is it all right if we have a son first, then 2 daughters?"

W: "I was thinking of a girl, then a boy, then another girl."

H: "The first-born really should be a boy. We talked about this last year, and you said that was o.k."

W: "You're right. In fact I'm going to call 1-999-BOYS-R-US right now!"

Narrator: Yes, it's true. Do you want a boy, guaranteed? Call 1-999-BOYS-R-US. Our trained counselors are standing by ready to answer all your questions and take your order for our new, patented, guaranteed BOYS-FOR-SURE home sperm separation kit. And, for those who definitely want a girl, we have just the thing. Call 1-999-GIRL-4 ME! (Editor's note: the phone numbers are made up, please do not call them!)


A successful method for preconceptual gender selection has recently been reported in the journal, Human Reproduction (volume 13, Issue 9, Sep. 1998). The article was based on research conducted by the Genetics and IVF Institute in Norfolk, Virginia, a highly regarded infertility program. Their method is called the Microsort sperm separation technique.

In researching the subject of gender preselection, I have come across many fascinating and unusual techniques. I'll discuss a few of the historically popular methods. Some can be done at home, others require medical intervention. Each technique seems to have its enthusiastic proponents and equally enthusiastic detractors!

The Microsort Method

The Microsort method is an expensive, high-tech approach to gender preselection. Normal semen contains about a 50-50 mixture of X-bearing and Y-bearing sperm. A common approach to gender preselection involves the separation of the X-sperm from the Y-sperm. The desired sperm population can then be introduced using a standard fertility technology (such as IVF or artificial insemination). Many have claimed success at this type of sperm separation, but few have been able to back up their claims with hard data, until now.

The Microsort method uses a technique known as flow cytometry. This technique exploits the one well-known difference between X and Y sperm, which is the amount of DNA present, which makes the Y-sperm a bit smaller and lighter than the X-sperm (actually a Y-sperm contains 2.8% less DNA than an X sperm).

Seminal fluid is filtered and then run through an extremely long, thin tube under pressure. This allows the sperm to line up, almost one-by-one. At the other end, the tube divides and there is a fluorescence-based switching mechanism designed to "steer" larger DNA sperm (X-bearing) one direction, and smaller DNA sperm (Y-bearing) a different direction. After the flow cytometry separation, the newly created samples were studied. The X-rich (bigger-DNA) sample contained 85% X-bearing sperm, and would therefore predict an 85% chance of conceiving a daughter. The other sample was determined to have only 65% Y-bearing sperm, predicting a 65% chance of conceiving a male child. Expect to pay about $2,500 per separation and insemination.

The September 1998 article reported on 29 clinical pregnancies to date, where the desired gender was female. Nine patients delivered 11 healthy babies, 7 resulted in miscarriage, and 12 were undelivered at the time of publication. Of the 14 pregnancies with known fetal gender, 13 were female, giving a success rate for female gender selection of 93%. Until more data is published, this method appears to be effective and legitimate. A report on their success with a male gender preference will be published soon.

For some reason, this method is better at producing girls than boys. (91% of the desired female babies have been female and only 76% of the desired male babies babies have been male).

Conception Rate (2006 data) The MicroSort Clinic average cumulative IUI clinical pregnancy rate is 16.6% (242/1452) per treatment cycle. The overall IVF/ICSI clinical pregnancy rate is 33% (164/497) This includes MicroSort collaborators doing IVF/ICSI.

For more information: Microsort Web Site

Microsort is available at the Huntington Reproductive Center location in Laguna Hills, California. Called Microsort West, they can be reached at (800-277-6607) or on the web at E-mail:

The Shettles Method

In contrast, a well-known low-tech do-it-yourself method of gender preselection has been developed and popularized by Landrum Shettles, M.D., Ph.D. In 1989 he published the revised edition of "How to Choose the Sex of Your Baby," Doubleday Publishers, New York. His theory is that Y-bearing sperm are lighter and therefore faster swimmers than X-bearing sperm, but less "hardy" (due to less DNA) than X-bearing sperm. Harsher conditions would favor a female fetus, such as lower sperm counts caused by heat, tight underwear or frequent ejaculations. Dr. Shettles claimed a 75% success rate for those wanting girls and an 80% success rate for those wanting boys.

The Shettles method is mainly based on the timing of intercourse. To achieve a boy, one must do the following. Ovulation prediction kits should be used twice daily. When the color changes, ovulation will occur within about 24 hours. Intercourse is limited to one attempt, the day after the color change, using a position that favors deeper penetration (gets the faster swimmers closer to their goal). Female orgasm just before male ejaculation is also recommended. This increases the alkalinity of the vagina, improving the penetration of the sperm through the cervical mucus. In addition, a caffeinated beverage for the male about one hour before intercourse may speed up the swimming of the sperm. Abstinence for 3-4 days before the timed intercourse is ESSENTIAL to this method. It builds up the sperm count and avoids the wrong timing, both of which might increase the odds for female. If intercourse occurs between the end of the period and the start of the abstinence "window", condoms should be used.

To improve the chances for a girl, the strategy is almost the opposite. Intercourse is advised frequently from the start of the cycle (after bleeding has ceased). Initially condoms could be used and vaginal spermicide avoided. Then, 3 days before ovulation normal intercourse should occur. This 3-day timing can not be determined with an ovulation kit. Instead, the woman needs to more or less know when she usually ovulates and count backwards from the next predicted ovulation. Also, the woman should try to avoid orgasm during the specified timed intercourse, and the missionary position is preferred.

Unfortunately, recently published data suggest that this method, despite Dr. Shettle's enthusiasm, may be no better than Mother Nature at achieving the desired sex. In 1984, the World Health Organization published a study that failed to confirm a gender predominance in relation to the timing of conception. A 1992 New Zealand study also failed to confirm the Shettles method. However, a 1993 study out of Nigeria examining gender preselection using the Billing's method supports the efficacy of timed intercourse for gender pre-selection. Similar to the Shettle's method, the Billing's method emphasizes cervical mucus checking, but also postulates that timing intercourse close to ovulation would increase the chances for a male child. A 96.3% success rate for those desiring a male child was reported! Perhaps there is merit to timed intercourse for gender selection after all.

The Whelan Method

A lesser-known book on low-tech gender selection, author Elizabeth Whelan, Sc.D., details a method that directly contradicts Shettles' theories. Basing her technique on the research of Dr. Rodrigo Guerrero of Colombia, Whelan states that Shettles' approach to timing intercourse only applies to couples undergoing artificial insemination.

She explains that for those partners conceiving the old-fashioned way, intercourse timed closer to ovulation is likelier to result in a girl and having sex earlier in the cycle will favor boy conception. Further, Whelan promises a lower success rate than Shettles: 68 percent for boys and 57 percent for girls.

Reference: (

The Ericsson Method

Other methods for medical sperm separation have been promoted over the years. One popular method is called the Ericsson method, which Dr. Ericsson patented. He charges a fee to any clinic that wants to offer his sperm separation method to patients. Semen is run through a human serum albumin separation column and then X-rich and Y-rich fractions are collected. After the separation, an artificial insemination is performed using the appropriate fraction. Normally, this is done quite close to the time of ovulation. Based on Dr. Shettles theory of timed intercourse, one would expect more males with this method due to the timing, regardless of whether or not the separation actually worked, and this is what has been found consistently. Interestingly, when the sperm samples were studied after the separation, they still seemed to be 50/50 X and Y.

In January 1998, Human Reproduction published an article by Hong Kong researchers who used the Ericsson method. They did careful DNA studies on the supposed X-rich and Y-rich fractions produced by the separation and found that each fraction still contained the original 50% ratio of X-bearing to Y-bearing sperm. However, the birth data told a different story! Out of 18 couples wanting boys, 13 delivered single boys and one had twin boys! This gave an 83% success rate for this method. They concluded that the Ericsson method did enhance the odds for a male child, but not by the previously thought mechanism. Maybe Dr. Shettles was right!


Selnas Method, BabyChoice, Jonas Method, Chinese Calendar, GenSelect, Smart Stork

These methods involve predicting or causing the sex of the baby depending on the day of fertilization using some type of "mystical" calendar or some magical vitamin or vaginal douche. There are many variations. They require some bizarre calculations using the stars, the sun, the horoscope, or some natural formula determined after "years of painstaking research". They all involve sending money to some company that promises amazing results with a money-back guarantee. Just try to get your money back.

These promoters and their web sites make me sick. They use pseudo-scientific language, yet in reality their explanations are scientifically impossible. However, since many people don't care about proof, they only care about how things sound, they will send their money and take their chances. These methods are a scam, are completely bogus, and anyone who spends money on them deserves to be fleeced.

A kit sold on the Internet by a company called GenSelect is reportedly making a difference in whether you paint the nursery pink or blue. GenSelect claims it can turn picking the sex of your baby from a crapshoot into a slam-dunk. "We've tallied up a 96 percent success rate," says Jill Sweazy, GenSelect's co-founder.

Web article about GenSelect Scam

Of course, GenSelect is being likened to PT Barnum: there is a sucker born every minute. In response to such doubts, GenSelect's Sweazy points out that "Opinion's opinion. You can find someone contrary to antibiotics. We were just granted our United States patent, and they don't grant patents to wives' tales." Well heck -- if it has a patent, it must work. Right?

Not really -- it is a common misconception that patents are only issued to inventions that actually work. If this was true, every ailment known to man would be cured (cancer, AIDS, hair loss). In order to be patentable, a disclosed invention only has to be novel (never done before), not obvious, and useful. If a patentee provides a use that is substantial and credible, the patent office must defer to the applicant. Only in rare cases will patent applications be rejected by the Patent Office on the basis of failing to provide a substantial and credible utility (perpetual motion machines, reincarnation, etc.)

So it isn't surprising that GenSelect may have received a patent on a gender selection kit. Far more interesting, however, is what did GenSelect actually patent? According to U.S. Patent No. 6,610,331 (the only patent listing the Sweazy's as inventors in this field) the Sweazy's claim is just a nutriceutical which improves the natural fertility process comprised of 15 different vitamins and supplements (see reference for full listing).

So the '331 patent covers a "nutriceutical" of several types of vitamins etc. The patented claims don't actually cover a gender selection kit -- more like a soup of various vitamins. Is it scam? Well, you have a 50/50 chance of the "gender kit" being right at any point in time.

Moral of the story: just because it says "patented" it isn't guaranteed to work and before assuming that the patent actually covers the product or "method" being sold, check out the actual claims first. Caveat emptor!

The Selnas Method

There is another purported method of gender selection being promoted on a web site called "babychoice." This is based on the dubious-sounding theory of variations in egg polarity that allows only male or female sperm to initiate conception on certain days. All you need to do is send money and you will receive a custom calendar telling you which days to have relations to obtain a baby of the desired sex.

Scientifically speaking, this is a ridiculous concept and makes no sense. For fertilization to occur, the egg is literally bombarded by dozens to hundreds of sperm. The tip of the sperm releases an enzyme whose purpose is to degrade the zona pellucida, a fuzzy, protein-based cloud surrounding the egg. After enough sperm have hit the egg, one finally gets in resulting in fertilization. This process is completely random as far as I know.

I consider this method nothing more than a scam based on pseudo-science and gullible patients. Please stay away from the Selnas method.

PGD: preimplantation genetic diagnosis

This is very effective method but is extremely expensive and some people have ethical problems with it. A couple must undergo in-vitro fertilization (IVF). This creates actual living embryos in a Petri dish. At a precise stage, usually day 4 or 5 after conception, one cell can be removed from one embryo without damaging the embryo is any way. This sounds hard to believe but it is true. This cell can then be tested using fluorescent-tagged DNA pieces which bind to specific sites on certain chromosomes, such as the X and the Y chromosomes. Using a fluorescence-detecting microscope, people can look at each cell and determine the sex of each embryo. Then the preferred embryos will be transferred into the woman's body for conception. I always wondered if they can remove a cell from a growing embryo and then make that cell into another embryo. Instant twins!

This method can be 99.99% effective but the probability of conception for each attempt (one attempt per month) is about 20 to 25 per cent.

Can you really find out the baby's sex at 5 weeks of Pregnancy?

Baby Gender Mentor Home DNA Gender Testing Kit by Accu-Gen Labs

This lab claims to be able to determine the sex of the baby as early as 5 weeks gestation. Then, if the pregnancy is of the non-desired sex, a pregnancy termination can be performed, preventing the "wrong" sex baby from being born.

The fetus releases small amounts of its DNA into your blood, and this can be detected and measured. If there is fetal origin Y-chromosome DNA in your blood, you are supposedly carrying a baby boy and if this is not detected, you are supposedly carrying a girl. They claim greater than 90% accuracy.

Many articles are written disputing the accuracy of this test, and NPR (National Public radio) did a report as well. Acu-Gen has released very little information about exactly how the test works. They consider that to be proprietary information. According to NPR's radio report, the company has explained previous inaccurate results as being the result of a vanishing twin, which is a fetus that stopped growing soon after fertilization.

"Until Acu-Gen releases its data, there's no way to know the test's reliability, said Sandra Carson, a professor of obstetrics and gynecology at Baylor College of Medicine who specializes in sex selection. "Until that's out, I think it shouldn't be on the market," she said. (Reference)

After viewing an ABC report about Baby Gender Mentor's problems and lack of oversight for the test, Florida Congressman Jim Davis has urged the FDA to investigate Acu-Gen and to regulate similar baby gender tests, and the Florida Attorney General has opened an investigation against Acu-Gen. (Reference)


The discussion of gender pre-selection is not complete without an ethical review. Some people question the appropriateness of couples trying to artificially choose one sex child over another. In some situations, gender preselection is highly advisable. There are many genetic conditions known to be inherited by sons, but not daughters. These are known as X-linked recessive conditions. Hemophilia, Duchenne's muscular dystrophy, and Fragile X-syndrome are examples. With these disorders, there is a damaged gene on the X-chromosome. A mother with a single abnormal X also has a normal X and is therefore unaffected. However, 50% of her male children will manifest the condition. It is logical to attempt conception of a female in these situations.

Couples considering gender preselection should be well informed. There can be costs and inconveniences associated with some methods of gender preselection, and the results are not one hundred percent. Many cities have centers which promote their methods and exaggerate their successes, so careful research is in order. Gender pre-selection should remain a personal decision, well researched, but ultimately best made by the parents-to-be. Current methods seem very promising, but there is data suggesting that some of the older, more popular methods may also work. In the near future, expect more than just gender selection. Soon, we will have designer embryos, with bits of DNA added or removed in order to shape the genetic traits of the offspring. Amazing stuff, but just a bit scary too!

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Copyright Bryan S. Jick, M.D. 2006. May be printed only with author's permission.