A few years ago, I wrote this blog post on determining gender of a pregnancy. I wrote it after having been asked the same question 10 times in the same week, and of course, repeating the same answer.
The same question comes up often. Very often. It’s a very human desire, to prefer one gender or the other for a certain pregnancy. This isn’t to say women are not prioritizing healthy babies, but of course, as long as the baby is health, it would also be nice if it could also be a….. There are lots of reasons, a family that has children of one gender, may hope for a child of the opposite gender. A woman that has always relied on her sister, may really want a sister for her daughter. A woman who grew up with an amazing older brother may really want her firstborn to be a boy.
Whatever the reason, patients ask this all the time. There is so much information on the web about this topic, much of it inaccurate, I decided to review the latest evidence on the subject to see if there is anything new.
The short answer has remained the same: Hope and prayer (free) or IVF with preimplantation genetic screening (PGS) (not free).
Some background: the gender of a pregnancy depends on whether an egg is fertilized with a sperm carrying an X (female) or a Y (male) chromosome. The factors that affect this process are vast, which is why it’s hard to interfere with them. Given the HUGE importance of gender balance in the stability of a population, it makes evolutionary sense that techniques within reach of the average person really have no bearing on the gender of a pregnancy. Attempts to control the process, however, have been discussed and taught as far back as ancient Greece, and probably a lot longer. In spite of all the variables affecting the fertilization of a specific egg by a specific sperm, women have a stable 51% chance of delivering a male fetus, independent of the gender of other children or the age of the parents.
“Natural” methods you will read about and may have tried:
There are a variety of diets out there, for both men and women, promising higher rates of girl or boy pregnancies. Things like increasing calcium or magnesium helps you to have a girl or sodium and potassium for a boy are a few examples. Eating more calories to conceive a boy vs less calories to feed a girl are other examples. None of these suggestions have been well studied. There is a study of 700 or so British women that showed women who had a higher caloric intake pre-pregnancy had a 55/45 ration of boys to girls. A follow up, much larger study of gender ratios after a famine in Holland showed no difference in the gender ratios than the well established 51/49.
Basically, eat what you like and prepare yourself for the 51% chance you’ll take a boy home from the hospital.
Male sperm swim faster and die sooner, so you’ll often read about having sex earlier in the fertility window to conceive a girl and closer to ovulation to have a boy. You may read something about the female partner having (or not having) an orgasm to influence gender. There’s even something about having sex no more than once a day or “all the time” to concentrate or dilute male sperm.
There are even two named methods: the Whelan method and the Shettles technique. They both teach that having sex 2-3 days before ovulation is more likely to result in a female fetus but they disagree on timing for increasing the chance of a male fetus. Both cite “studies” that prove them right.
Though very interesting, studies that have tried to correlate timed intercourse with gender outcome do not show any consistent trend–and there are many.
If you are trying to conceive, have sex as often as you like during the fertility window and remember that hope and prayer are probably equally effective (if not more effective) than any manipulation of “timing” your sex.
The Shettles method also includes advice on sexual position. Arguing the lower part of the vagina (nearer the labia) is more acidic, the method advises deep penetration and orgasm to increase the chance of a male fetus. While depositing sperm nearer the opening of the vagina, where’s it more “acidic”, would be more likely to result in a female fetus. There has been no studies or data to suggest any sexual position affects gender ratios.
Gender selection kits
There are now multiple “kits” available online for purchase. Taking specific, proprietary nutritional supplements and other advice, all based on principles of changing the “ionic” composition of the blood or the pH of the reproductive track. These site all claim success rates of over 90% in conception of the gender of choice, none have published any of their data in a peer-reviewed journal.
Initially, there was some data that sperm separation prior to intrauterine insemination (IUI) was helpful in increasing a couple’s chances of conceiving the gender of preference. Based on the known characteristics of male sperm (Y-carrying): smaller heads, faster swimmers and have a lower negative “charge”. There are various sperm separation techniques offered to patients to use pre-IUI. The “preferred” type of sperm is then given back to the couple for IUI or used in IVF for conception.
Unfortunately, more recent data hasn’t shown that much of a difference between separated samples. When more intensive techniques (like FISH) are used to test the sperm from the two groups, they most often show a 50/50 split of X/Y sperm. You can read just a few of these studies here or here or here or here or here.
So, save the money you would have paid for separating out sperm and paying for IUI and put it in the college fund for your future child, knowing there’s a 49% she’ll be a girl.
What works: Preimplantation Genetic Screening:
For couples undergoing IVF treatment (In Vitro Fertilization), there is an option to have preimplantation genetic screening (PGS) performed before transferring an embryo back to the uterus. This is a cell biopsy, after fertilization of the eggs by sperm, which tells you the chromosomal make-up of the embryo. Along with gender, this technique can rule out other chromosomal issues in the embryo. There are also certain genetic conditions a couple can only pass to a child of a specific gender and PGS helps solve this issue by selecting the gender that could not possibly be affected. However, that is not the most common reason gender selection is being done. IVF clinics offering gender selection report that over 93% of cases are done for “family balancing”. This is when a family wants a gender they do not already have to “balance” out their family’s gender balance. Depending on the clinic, this may or may not delay transfer of the fetus back to the uterus to the next cycle. Cost is usually $2000-$5000 in addition to other IVF costs. However, IVF success rates after PGD are higher, since only chromosomally normal embryos are transplanted.
As you can imagine, at this level of technologic intervention, you can choose the gender of your pregnancy accurately. There are a lot of ethical questions around this type of parental decision making and every major reproductive organization out there has an ethics statement on “gender selection” via PGS. But that’s a discussion for another day…
And there you have it, we haven’t come very far since the ancient Greeks in terms of easily accessible ways to conceive a child of our preferred gender. Looking at the big picture, that’s probably a good thing.
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