When Sarah and Bill found out that they were expecting twins, they became incredibly overjoyed. But their joy was soon mixed with worry when doctors discovered that the children were so-called monochorionic twins, or identical twins that share a placenta and an inner amniotic sac. Such a pregnancy presents big risks, so Sarah was hospitalized for 57 days before giving birth to the twins via a cesarean section. But when the twins were born, everyone in the maternity ward witnessed something unbelievable. The twins were born within 46 seconds of each other and doctors soon realized that everything had gone well—both…