how do prenatal paternity tests work?

Question

When I tried googling this, I got a ton of adds for companies selling these tests, but not a whole lot of information. I know it has something to do with babys DNA being present in moms blood, but how do the tests distinguish between moms and babys DNA?

In: Biology

Answer 1

The baby has a sac of fluid around (the thing that breaks when someone’s ‘water breaks’) that is full of baby’s cells. A needle can be inserted to draw up some of that fluid (amniocentesis) for testing.