Third Generation IVF Technology and Gender Selection
In clinical practice, many families have good expectation of having two children to make up the word ‘good’, and have also heard that the third generation IVF technology can screen genes and chromosomes, so they often ask if they can ‘customise’ a pair of dragon and phoenix babies with the help of this technology. They often ask if it is possible to ‘customise’ a couple of twins with the help of this technology. Below, I will explain in detail from a professional point of view.
Disease, not gender, is the core purpose of IVF screening
Technically speaking, IVF-3 is indeed able to differentiate the sex of embryos. However, its main purpose is not for gender selection, but for disease screening. Third generation IVF, medically known as Preimplantation Genetic Diagnosis / Screening (PGD/ PGS), is not only suitable for infertile patients with fertility needs, but also of great importance for people with genetic disorders. It allows genetic testing of embryos before implantation to diagnose genetic problems and to screen for embryos that are genetically normal for transfer, thus preventing the acquisition of hereditary diseases in the offspring.
Gender Screening in Special Circumstances
So, under what special circumstances can the gender of the embryo be selected? Sex selection is possible when the patient is suffering from a sex chromosome-linked genetic disorder that is ‘transmitted to males but not to females’ or ‘transmitted to females but not to males’.
Human cells contain sex-determining sex chromosomes, XX for females and XY for males, and if the disease-causing gene is located on a sex chromosome, there is a pattern of companion inheritance. If the causative gene is located on the sex chromosomes, the disease is called an X-linked disorder, and if the causative gene is located on the Y chromosome, the disease is called a Y-linked disorder. Most of the known sex chromosome-causing genes are located on the X chromosome, and X-linked recessive disorders are more common.
In haemophilia, for example, the causative gene is located on the X chromosome, which is classified as an X-linked or X-sex-linked disorder. Since women have two X chromosomes, it is very difficult to have the disease-causing gene at the same location on both chromosomes. The disease-causing gene on one X chromosome is usually masked by the normal gene on the other X chromosome, so women do not show symptoms. Males, on the other hand, have only one X chromosome, and as long as the causative gene is present on that X chromosome, the disease is bound to develop, which is why haemophilia is almost exclusively a male condition.
To avoid giving birth to a baby with haemophilia, third-generation IVF can be used to perform genetic testing on the embryos and select normal embryos for transfer, thus effectively avoiding the transmission of this sex-linked genetic disease.
In summary, the core purpose of the third generation IVF technique is disease screening, not gender selection. Fetal gender screening can only be performed in specific cases where there is a possibility of having a baby with a sex-linked genetic disease. It should also be clear that IVF is essentially a medical technique to help couples of childbearing age realise their desire to become parents, and is not a routine means of producing twins or phoenix babies. Finally, it is sincerely hoped that all patients will not be overly concerned about the sex of the foetus, whether it is a multiple or a single foetus, but rather the success of assisted conception and the birth of a healthy baby is the most crucial.