In nature, gender of the baby is a completely random event and there is no scientific evidence to the contrary. Furthermore, there is strong evidence that couples with multiple children of a single sex are not predisposed to having children of that sex.

The gender preference is very common, with about 40% of couples desiring to choose the gender of their baby, with about an equal number interested in a male and a female.

There are two techniques for gender selection: sperm-sorting and PGD.

SPERM SORTING

The patent for sperm sorting using flowcytometry is owned by the US government. It was developed for use in farm animals and is exclusively licensed to XY, Inc.

MicroSort, has adopted the technology for use in humans and is the only organization in the United States that performs sperm sorting as a part of an FDA pre-marketing clinical research project.

In an unsorted sperm sample there is an equal ratio of sperm cells bearing X chromosome (female) as Y chromosome (male). After sperm sorting in bulls, it is possible to achieve a 90% enrichment with either X or Y chromosomes bearing sperm cells.

Sex sorting in humans appeared to be less efficient: 80-90% for X chromosome (female) and only about 60-70%% for Y chromosome (male).  The overall experience with sperm sorting in humans is small and more time will be needed to tell with certainty that the technique is safe and does not diminish the developmental capacity of spermatozoa or introduce abnormalities into the baby.

Recent study in sows shows that after freezing-thawing sex-sorted spermatozoa, despite retaining their ability to fertilize an egg, did not produce viable embryos as all pregnancies ended in a miscarriage.

Even though no comparable study in humans has been published, sex sorted human sperm also loses its ability to support pregnancy after freezing/thawing and therefore cannot be shipped frozen to outside physician.

Since it cannot be frozen and transported, you would have to travel to one of the two Microsort locations for intrauterine insemination or an IVF cycle.

PGD FOR GENDER SELECTION

PGD for gender selection is very accurate. As will any other PGD, it involves embryo biopsy which may decreases an embryo's chance of implantation. However, in experienced hands this is less common.

One of the common mistake made when a couple is looking for gender selection is asking to test for more chromosomes. On the surface this seems to make sense since embryo manipulations have to be done anyway. However, including more chromosomes into testing always means more errors resulting in the very real risk of exclusion of some normal embryos from transfer (in one study as many as 40% of normal embryos were diagnosed as abnormal with probes for 5 chromosomes).  This also means that testing will take more time and the results will not be available until day 5 of in vitro culture.

Therefore, if your sole motivation for having an IVF is gender selection, it is prudent NOT to request testing for more chromosomes than X and Y (those two determine the gender).

Another frequent dilemma for patients is whether to still proceed with PGD if only a few embryos are available.

If the patient's priority is gender selection, it is reasonable to go ahead with PGD even if only a very few (some times only one) embryos are available.

On the other hand, if your first priority is pregnancy and gender selection is second, it is wise to postpone a desicion about PGD until the tentative day of embryo biopsy (3 days after egg retrieval). Play it by the embryologist. Let him/her decide if you have a sufficient number of good quality embryos to proceed with PGD without affecting your chance of pregnancy.

100% GENDER SELECTION GUARANTEE

It is not uncommon to see 100% guarantee in gender selection ads. Such guarantee is indeed possible. Remember, however, that it only applies to gender. It does not mean that the pregnancy is guaranteed.

Such guarantee may some times backfire. This is because an embryo with inconclusive gender determination result would be excluded from the transfer as its gender cannot be guaranteed with a 100% certainty, even though it may be the best embryo in the cohort and is in fact of desirable gender (or may be not).

Therefore, it is important to make it very clear to your doctor, whether you want to go along with 100% guarantee or would rather take a small chance of uncertainty in gender selection but increase your chances to get pregnant.

CHOOSING THE PLACE FOR PGD

ETHICS OF GENDER SELECTION

The central ethical issue involved in gender selection is disposition of embryos of undesirable sex. Some couples chose to donate them, but a majority prefer to have them discarded.

Is this ethical?

This is a private question and every couple decides for themselves.