When the ultrasound shows two separate placentas, and that the babies are of the same gender, you may have to wait until the very delivery for your answer. Only after your babies arrive, your doctor will be able to find out whether they were sharing one placenta. There may also be a necessity to conduct some additional laboratory tests in order to tell how many placentas there were, as two separate placentas may sometimes be fused together and appear as one.

It is also possible that even the placental analysis may not solve the problem, and then you will have to order an at – home DNA test, which costs somewhat around $100, but it will be necessary to wait for a week or two for the result to be obtained. As it has already been mentioned, monozytogic twins almost always have identical DNA, while dizygotic twins usually share about 50% of their DNA.

Why is it so Important to Know Whether Your Twins are Dizygotic or Monozygotic?
As a rule the question of finding out whether the twins you are expecting are dizygotic or monozygotic is the matter of a pure curiosity, though, sometimes this kind of analysis may be conducted for some certain medical reasons.
Sometimes monozytogic twins, who have the same placenta for two run some health risk during the pregnancy period. Up to 15% of them develop the “twin – to – twin transfusion syndrome” (TTTS). This condition is an extremely dangerous at least for one of the twins, as the second so – to say, “donates” all his fluids to himself. The twin, which is on the receiving end, usually grows and develops more rapidly than the donor twin does.

In case if no kind of treatment is appointed and conducted, both babies risk to die. If it becomes clear that the babies you are expecting, have one placenta for two, your doctor will have to look after their weight gaining and watch for another signs of the TTTS. In case if any symptom of the TTTS is suspected, correct treatment, conducted in time will help prevent all possible complications and keep your children alive and healthy.

You may need to know whether your twins are dizygotic or monozygotic even after they become older. There may happen, that one of them may have some kind of a genetic disease, and if the twins are monozygotic, the second child will for sure suffer from the same disease too. A dizygotic sibling may be spared on the other hand.
And of course, while going for a walk with your twins, you will be asked this question thousands of times, so, get ready to give an answer, whether your children are fraternal or identical to nearly every person in the street.