Chromosomally normal babies get 22 chromosomes and a sex chromosome from each parent. Women only have X sex chromosomes, and so each of her eggs will have 22 chromosomes and an X sex chromosome. Men carry both an X and Y sex chromosome, and each individual sperm will carry 22 chromosomes and either an X or a Y sex chromosome. The distribution of X and Y sex chromosomes in each semen sample tends to be tilted slightly in favor of X, studies have found that 52% of sperm carry an X chromosome, while 48% carry a Y. Your baby’s gender is determined by the individual sperm that fertilizes the egg.
Patients typically consider gender selection for two reasons:
There are a couple of methods of pre-fertilization sex selection that have been in use and evolving in effectiveness for decades, but these methods are inexact. To better understand how sperm sorting works, it is important to understand the nature of sperm.
Interestingly, sperm that carry an X chromosome contain MORE genetic material that those that carry a Y chromosome (about 2.8% more in fact). This is because the X chromosome itself is larger. This 2.8% difference in genetic material means that X chromosome sperm are ever so slightly heavier than Y chromosome sperm. It also means that when stained with specific fluorescent dyes, the X chromosome sperm appear to glow more intensely than Y chromosome sperm when viewed with ultraviolet light. The larger X chromosome absorbs more dye than its smaller Y chromosome counterparts. All sperm sorting methods leverage the difference in genetic material in different ways to achieve the goal of separating individual spermatozoa in each sample into X and Y groups.
The success rates of various sperm sorting techniques has improved over time, although published studies vary somewhat in their findings. Generally, sperm sorting is likely to have a 70% - 85% chance of successfully selecting a female, and 60% - 75% for male. There are however several unknowns with many of the techniques used in sperm sorting methods. The fluorescent dyes used in older techniques are effective because they bond to the DNA and RNA of spermatozoa. This raises concerns over potential DNA damage and the impact to embryo development, hatching, and implantation rates. Newer stains that only attach to dead or dying spermatozoa, hoping to eliminate or reduce collateral damage to otherwise healthy sperm, have not yet been well studied.
Aspire does not presently offer sperm sorting as a method of gender selection. The relative gender uncertainty of a successful pregnancy, when considered with the potential for poorer outcomes in general lead us to suggest an alternative approach, IVF with PGD.
IVF with PGD has several advantages over conventional sperm sorting techniques. First and foremost, IVF with PGD has a greater than 99% likelihood of correctly identifying the sex of each embryo tested. Additionally, PGD also determines which embryos are genetically abnormal. These abnormalities can prevent normal embryonic development or have a serious impact on the health of your baby. See our PGD and PGS page for more information.
IVF with PGD is a process and before we can perform PGD, you must first complete pre-cycle preparation, ovarian stimulation, and egg retrieval. We then perform ICSI to fertilize your eggs. The resulting embryos are incubated and closely monitored for normal cell development for 5 days. On day 5 and day 6, our highly skilled embryologists carefully biopsy one to two cells from each viable embryo. The embryos are then cryogenically frozen through a process called vitrification. Because it has been shown to improve outcomes, Aspire recommends delayed embryo transfers for all patients. Delayed embryo transfer also allows us the diagnostic time needed to perform PGD. Once PGD results are available, we will be able to identify the healthy male and female embryos. We can then transfer only the gender of your choice.
Unlike some clinics that may charge piecemeal for all these services, Aspire believes in transparent upfront pricing. Our pricing may vary slightly depending on which Aspire market you live in, so please contact us to inquire about current pricing. Our team of professionals can check your insurance benefits to see if any coverages exist for IVF with PGD. Insurance benefits vary widely, but if you don’t have coverage, Aspire has relationships established with selected financing companies and can help with the application and approval process. In addition to the fees due to Aspire, IVF with PGD patients should expect costs associated with IVF medications prescribed during ovarian stimulation, as well as anesthesia costs incurred during egg retrieval. These may be billed from a separate provider. Any fees for office visits, lab work, or other services performed by Aspire prior to beginning a IVF with PGD cycle are also the responsibility of the patient. You may have a deductible and/or copay due for visits prior to beginning your cycle. Our trained financial counselors can help answer questions and guide you through the process.