The birth of twins is related to genetics and it is generally recommended to let nature take its course, without human intervention. If ovulation stimulants or in vitro fertilization (IVF) are used, consultation with a physician is required as there are strict indications. 1. Genetic predisposition: If both or one of the pregnant couple has the genetic predisposition for twins, the chances of having twins in a natural pregnancy will be greatly increased. 2. Ovulation-promoting drugs: The organism induces follicular development and ovulation by taking ovulation-promoting drugs such as clomiphene citrate capsules and letrozole, which may also lead to twins. However, there is a possibility of ovarian hyperstimulation syndrome, such as dizziness, nausea and impairment of liver and kidney functions. The use of medication needs to be under the guidance of a doctor and should not be used on its own. 3. IVF: Growing two embryos through in vitro fertilization-embryo transfer can also increase the probability of having twins, but IVF also involves certain risks. If you encounter any of the above problems and have any questions, it is recommended that you consult a professional doctor and take the health of your baby as the main concern.