A prenatal genetic test can be done by samples like blood, cell-free DNA, and some specific type of ultrasound.
These prenatal tests are usually done in the 1st and 2nd trimesters of the pregnancy. And although screening tests don’t tell about birth defects they can warn about the presence of a genetic disorder.
A sex blood test is a non-invasive prenatal test. In this test blood sample is used to determine the gender of the fetus. And since it is a non-invasive test it has less risk of problems related to pregnancy like miscarriage, leakage of amniotic fluid.
The analysis of prenatal diagnostic tests is done by different techniques such as:
By arranging the images of chromosomes from largest and smallest and detecting any kind of abnormalities in them.
By using Fluorescence in situ hybridization to detect the number of chromosomal abnormalities.
Why do a gender blood test?
Generally, sex-linked disorders are recessive disorders linked to the X chromosome and exclusively occur in males as they only have one X chromosome. A blood test to find out the sex of the baby is generally useful in the child who has a high-risk f developing a genetic disorder and although prenatal screening is not accurate the result of the test varies in different cases.