The best age for a woman to have a baby is between 22-28 years old, because this is the period when she is more normal in all aspects, her reproductive system is developed and healthy, her egg cells are of the highest quality and her physiology is mature. Women have about 400-500 mature oocytes in their lifetime, and generally only one mature oocyte is expelled a month, so humans are singleton animals and most of them have only one baby at a time. If you get pregnant too early or too late, you are likely to have abnormal fetal development, especially if you are older than 36 years old, the probability of fetal malformation is very high.