Prenatal sex discernment

This article is about prenatal sex discernment in humans. For other uses, see Sex determination.

Prenatal sex discernment is the prenatal testing for discerning the sex of a fetus before birth.

Methods

Prenatal sex discernment can be performed by preimplantation genetic diagnosis before conception, but this method may not always be classified as prenatal sex discernment because it's performed even before implantation.

• Cell-free fetal DNA testing, wherein a venipuncture is performed on the mother to analyze the small amount of fetal DNA that can be found within it. It provides the earliest post-implantation test. A meta-analysis published in 2011 found that such tests are reliable more than 98% of the time, as long as they are taken after the seventh week of pregnancy.
• Chorionic villus sampling (CVS) and amniocentesis are two rather invasive testing procedures. These may, in principle, be performed as early as the 8th and the 9th week of pregnancy. The difficulty of these tests and the risk of damage to the fetus, potentially resulting in miscarriage or congenital abnormalities (especially when done early during the pregnancy), make them quite rare during the first trimester. In the United States, CVS and amniocentesis are most commonly performed after the 11th and the 15th week of pregnancy.
• Obstetric ultrasonography, either transvaginally or transabdominally, can check for the sagittal sign as a marker of fetal sex. It can be performed between 65 and 69 days from fertilization (week 12 of gestational age), where it gives a result in 90% of cases - a result that is correct in approximately ¾ of cases, according to a study from 2001. Accuracy for males is approximately 50% and for females almost 100%. When performed later, after 70 days from fertilization (at week 13 of gestational age), it gives an accurate result in almost 100% of cases.

Applications

Potential applications of prenatal sex discernment include:

• A complement to specific gene testing for monogenic disorders, which can be very useful for genetic diseases with sex linkage, such as, for example, X-linked diseases. In such cases, it may be much easier to exclude the possibility of disease in the child by prenatal sex discernment than to test for any specific sign of the disease itself.
• Ability to prepare for any sex-dependent aspects of parenting.
• Sex selection, which after preimplantation genetic diagnosis may be performed by selecting only embryos of the preferred sex, or, after post-implantation methods by performing sex-selective abortion depending on the test result and personal preference. A 2006 survey [1] found that 42 per cent of clinics that offer PGD have provided it for sex selection for non-medical reasons. Nearly half of these clinics perform it only for "family balancing", which is where a couple with two or more children of one sex desire a child of the other, but half do not restrict sex selection to family balancing. In India, this practice has been used to select only male embryos although this practice is illegal {{PNDT ACT NO. 57 OF 1994}}. Opinions on whether sex selection for non-medical reasons is ethically acceptable differ widely, as exemplified by the fact that the ESHRE Task Force could not formulate a uniform recommendation.

Legal status

India

Sex determination ban in India

Prenatal sex determination was banned in India in 1994, under the Pre-conception and Prenatal Diagnostic Techniques (Prohibition of Sex Selection) Act. The act aims to prevent sex-selective abortion, which, according to the Indian Ministry of Health and Family Welfare, "has its roots in India’s long history of strong patriarchal influence in all spheres of life". However, Supreme Court raps Central Govt. for "Sloppy" implementation of PNDT Act