Hallow, I have read your query and have understood your concern. It is not that every time the twins are due to two eggs. Some times, in a single fertilized egg after its first division the resultant two cells separate and start producing different children leading to twin pregnancy. In such cases, both the children are of the same sex and also they are identical to appear and behave. Though twin pregnancies are known to repeat in the families, you cannot guarantee that every pregnancy will be a twin pregnancy. However, the chances of twin pregnancies are more who have history of previous twin pregnancy. After you conceive, ultrasonography can help you to find out the number of embryos in your uterine cavity. And now with the advanced medical science and facilities, even twin pregnancies can be managed successfully. Please have no stress and tension of twin pregnancy. If you wish to have one more child, please go for pregnancy. I hope I have counselled you sufficiently.