A "test-tube baby" refers to a baby conceived through a process called in vitro fertilization (IVF). In this procedure, an egg from a woman is combined with sperm from a man in a laboratory dish, or "test tube," to create an embryo. Once the embryo develops, it is implanted into the woman's uterus, where it can grow into a baby. This method is often used by couples facing infertility issues. It allows for the possibility of conception when traditional methods have not been successful. Advances in reproductive technology have made IVF a common option for many families.