How can I ensure I get pregnant with a girl (or boy)?

by Sarah Azad, MD

A common question in all OB/GYN offices, I decided to finally write something down.  The internet it so full of misinformation about this topic, I hope this adds a drop of truth to what’s out there.

The short answer:  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 world, 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.

Ineffective things you will read about and can try:

  • Diet

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.  Some have been better studied than others.   Some have a study (or two) that show they work.  However, none of the diets that have been studied (including the above) have ever consistently shown success in affecting gender outcomes.  Even ones that tout “studies” that show higher rates of one gender over another have other studies that show the opposite or no effect. 

Basically, eat what you like and prepare yourself for the 51% chance you’ll take a boy home from the hospital.

  • Timed intercourse

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 that teach two opposite techniques: one teaches to have sex 3 days before ovulation to increase your chances of a girl, the other teaches to have sex 3 days before ovulation to increase your chance of a boy!  Both claim “studies” that prove them right.   That’s the internet for you.

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.

  • Sperm separation

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 fact that male sperm (Y-carrying) have smaller heads, are faster swimmers and have a lower negative “charge”, various sperm separation techniques are offered to patients.  The “preferred” type of sperm are 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. 

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.  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 chose the gender of your pregnancy pretty 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.