There are many reasons to perform fetal DNA testing, the most controversial of which is arguably to determine the paternity of the fetus. Most people are only familiar with paternity testing through dramatic reality shows, where adults with conflicting perspectives on who the father of a baby is have the paternity of the child confirmed by the host. The host themselves most likely had no part in conducting the paternity test—they just read the test results out to the guests and the audience. Those with a more invested interest in genetic testing may find themselves asking the following questions: What do the test results look like? How do you interpret them? What part of the DNA indicates if a man is the father of a child or not?
Here’s a breakdown of the science behind fetal DNA testing for those who are curious.
How a Paternity Test Works
Determining the biological father of a child can be described, in the simplest terms, as a matching game. In order for the child to be matched with their father, all possible fathers must be included as pieces of the puzzle; the most a testing center can do without the right puzzle piece is eliminate all other pieces as the correct match.
In reality, these puzzle pieces represent the DNA profiles of each individual. Fetal DNA testing involves obtaining a DNA profile of an unborn child through a blood sample from the mother. The fetal DNA profile is then compared to the profiles submitted by the potential fathers, which can be obtained through blood samples or other, more unusual samples, such as hair or semen stains. While it is obvious who the mother of the fetus is, her DNA profile is also required to match the pieces of the puzzle. This is because the baby has inherited half of its DNA from its mother and other half from its father.
What’s in the DNA?
A small fragment of every individual’s DNA is selected for comparison in the fetal DNA testing process. This fragment is called a Short Tandem Repeat (STR)—a section of the DNA that codes for a particular gene. The STR consists of 2-13 nucleotides that repeat themselves a number of times.
Multiple STRs are used to create a genetic profile for the child, the mother and the potential father(s). Any of the child’s STRs that are completely identical to that of their mother are eliminated from the analysis; the remaining STRs are compared to those of the potential fathers. The father of the child will reveal himself by matching with the child in these remaining STRs.
At Prenatal Genetics Laboratory, we offer prenatal genetic testing services to determine the paternity and/or gender of your baby. Our testing process is efficient, confidential and accurate, and the costs for our services are more economical than those of comparable genetic testing centers. With nearly two decades of experience in the industry, we can guarantee a reliable and convenient testing experience. Contact us today for fetal DNA testing!