Much is being offered by practitioners and on the internet as allegedly effective treatment options for gender selection/sex selection. The truth, however, is that real working options are rather limited.
More specifically, there are only two options which studies have shown to be effective: One is IVF combined with PGD/PGS, which can determine the gender of each embryo, created by IVF, before the embryos are transferred into the uterus. A second option, so-called sperm sorting, is based on the fact that it is the male who determines the sex of the child by either contributing an X- or Y-chromosome (the female always contributes an X) through his sperm. Each sperm, therefore, is either X- or Y-bearing.
The concept of sperm sorting is, therefore, based on enriching semen either for X- or Y-bearing sperm. Many techniques of sperm sorting have been propose over the years (for details, see below) but only one has ever been proven to, indeed, be able to affect the usual 50/50 ratio of X and Y sperm. It is a proprietary technique called MicroSort®. After completing a many-year long clinical trial, in which our center participated, this technique is currently under review by the Food and Drug Administration (FDA), and therefore clinically not available in the U.S. for elective gender selection. The FDA now only extended use of the trial for married couples with established sex-linked diseases. Once it becomes available again for elective gender selection, our website will reflect this fact.
Let us review the various procedures offered in the marketplace a little more in detail:
As previously noted, this method is based on the long-recognized principle that the male partner’s genetic contribution determines the sex of offspring by either contributing an X-carrying or a Y-carrying sperm to the fertilization process. Women, with XX sex chromosomes, of course, always contribute an X-chromosome. Consequently, based on the male contribution, the resultant embryo will be either XY (male) or XX (female).
Recognizing the importance of the male contribution to gender selection, various historical claims of success have been made, based on the alleged ability to separate X-bearing sperm from Y-bearing sperm. Unfortunately, until recently, nobody could prove that their method really worked in improving odds towards one gender or the other. MicroSort® was the first sperm sorting technique ever proven to be effective in changing the 50/50 ratio of X- and Y-bearing sperm. The technique is based on the labeling of sperm with a fluorescence marker that can then be picked up by a so-called fluorescence cell sorter.
In our opinion at the Gender Selection Center, MicroSort® represents the only sperm sorting technique ever proven to have a significant effect on gender distribution. Based on births after treatment, published data from the MicroSort® trial suggest that sorting for female will be approximately 90% successful, while sorting for male will be approximately 85% successful. In other words, sorting for female will still result in a male birth in approximately 10% of the cases, and sorting for male in approximately 15% will result in delivery of a female.
In Vitro Fertilization (IVF) and Preimplantation Genetic Diagnosis (PGD)
In contrast to sperm sorting, this technique is a so-called post-fertilization technique. This, for ethical and/or religious reasons, may be an important distinction for some patients. Here, embryos are first produced via the fertilization of the woman’s eggs with the partner’s semen (IVF). Then, the embryos are tested for their gender/sex.
This means that the technique will almost always produce embryos of the unwanted gender, later raising the ethical and practical question of what to do with those embryos. Options are (1) to cryopreserve (freeze) them for potential future use; (2) to donate them (usually anonymously) to infertile couples; (3) to donate them to CHR for research purposes; or (4) to ask CHR to dispose of them in an ethical way.
The process involves the woman undergoing an IVF cycle. Embryos generated in this IVF cycle undergo PGD/ PGS on their third day after fertilization, when they usually have reached 6-8 cell stage. At this point, one of these cells is microsurgically removed from each embryo and its chromosomes (amongst them the X- and Y-chromosome) are analyzed, allowing us to determine whether the embryo is female or male. Once each embryo is defined in its gender, only embryos of the desired gender are transferred back into the woman’s uterus, virtually guaranteeing a pregnancy of the desired gender. This technique is, therefore, much more accurate than sperm sorting in predicting the gender of a pregnancy.
Using IVF and PGD for gender/sex selection has additional advantages and disadvantages. A clear additional advantage is that, at the same time as examining the gender of each embryo, other chromosomes can also be checked. The most common chromosomal abnormalities in human embryos, such as Down syndrome, can be ruled out with considerable accuracy. One of the possible disadvantages is that the micromanipulation of the embryos may marginally reduce its chance for implantation in the uterus. However, data available so far suggest that the risk for birth defects is not increased following gender selection with IVF and PGD.
Before deciding to pursue this technique of gender selection, we strongly recommend further discussion of the advantages and disadvantages of available techniques with your physician. You should also review the costs for each of these options with your physician’s staff. A final choice is, in the end, both a medical and an ethical decision.
We also want you to be familiar with other genders election option being offered. Since we do not consider them “effective,” we cannot recommend those. Here is, therefore, a complete listing of various gender selection treatment options you may find on the web. We list these other techniques only to provide you with accurate information about them. Already introduced to you were:
Other, not recommended techniques are:
* CAUTION: Investigational device. Limited by federal (or United States) law to investigational use.
Further information about Gender Selection can be found on this site or Center for Human Reproduction’s parent site. Please refer to this page on Gender Selection