Male patients with Down syndrome are generally infertile, while female patients are partially fertile. Male Down’s patients are generally not fertile due to sperm quality; whereas female Down’s babies grow up partially with normal ovarian function and are potentially fertile; female patients with abnormal ovarian function are infertile. Down syndrome is a disorder caused by a chromosomal abnormality, also known as trisomy 21, which is caused by an extra chromosome 21. The mother’s advanced age, heredity, and teratogenic material factors are the main causes. Patients with Down syndrome mainly show congenital mental retardation, abnormal development of organs such as certain congenital heart diseases, and special appearance such as wide eye spacing and small eyelids. Female patients are partially fertile. However, the likelihood of passing it on to the next generation is very high, up to 50%. Therefore, genetic counseling is mandatory if a person with Down syndrome intends to have children.