I want to do a DNA test to establish whether a baby my wife is carrying is mine. Is it possible to do a DNA test while she is still pregnant? If so, at what stage of pregnancy can it be done, and is blood used or another sample? Is it also possible to conduct a DNA test using the remains of a buried person? Anonymous
Dear Anonymous,
A DNA test is done to find out the genetic make-up of any living thing, including persons. It can tell who the father, mother, brother, sister or cousin of a person is or is not, based on the genetic make-up of those tested.
When done between a father and child, a paternity DNA test can verify whether someone is the father of a child or not. If done later, samples of blood, hair, teeth, fingernail clippings, cheek swabs, used toothbrushes and blood stains may be used. When done earlier, while a woman is pregnant, a father may get immediate peace, apart from easily planning finances.
I do not know which hospital you went to or in which country you did the DNA test, but generally, the earliest DNA paternity test can be done from 49 days (or seven weeks) from the first day of your last normal menstrual period, without harming the mother or baby.
This is called a non-invasive prenatal paternity test. Here, the unborn child’s DNA from the mother’s blood, together with blood, hair, teeth, fingernail clippings, cheek swabs or used toothbrush samples from the alleged father, are used.
Other methods may also be used, including one done at 10 to 13 weeks of pregnancy, where placental tissue may be collected through the abdomen or cervix, and another that uses the water surrounding the baby (amniotic fluid) at 15 to 20 weeks of pregnancy.
However, these methods may be harmful. The latter two methods are invasive and may cause miscarriage, pregnancy infection, leakage of amniotic fluid, injury to the foetus and many other complications.
People who died and were buried recently, or even thousands of years ago, can still have samples taken for DNA studies, provided they were not cremated.
However, with time, the quality and quantity of usable DNA degrade. In this case, when a person has been dead for a long time, bones on the hands and feet, as well as teeth, which protect genetic material from decay, are usually used.