You can’t have a child with an xyy chromosome. Chromosome type xyy is an extra y chromosome in a male fetus, which is a condition caused by an abnormality of the y chromosome. Its formation may be due to an abnormality in the formation of sperm and the non-separation of the y chromosome during meiosis of gametes, which creates the cause of the extra y chromosome. The probability is that a fetus with xyy chromosome will show symptoms such as abnormal development of internal and external genitalia and mental retardation, called xyy syndrome. Therefore, after the diagnosis of xyy chromosome, from the perspective of eugenics, it is recommended to terminate the pregnancy as soon as possible. The couple should not prepare for pregnancy for a short period of time, and should carry out chromosome karyotyping tests for both sides, and if necessary, need to use assisted reproductive technology to help pregnancy. It is recommended that the couple go to the hospital for a pre-pregnancy eugenics health checkup to assess whether the body is suitable for pregnancy; quit smoking and drinking, and develop good habits to maintain good health, avoid prolonged exposure to radiation or pollution in the environment, and detach themselves from toxic and hazardous work environments.