When he learned that the fetus in his wife’s womb was “Fernando” syndrome, Mr. Wu, 37, had extremely mixed feelings. Mr. Wu is deeply influenced by the traditional thinking that there are three unfilial children and no children are the greatest. In order to have a male child, Mr. Wu has made a lot of efforts. In a friend’s introduction, Mr. Wu met a “doctor”, claiming to guarantee the birth of a boy, and never misses. The two couples in Mr. Wu under the guidance of the doctor, and the injection and medicine, and flushing, the money spent a lot, finally pregnant. The company’s main goal is to provide the best possible service to its customers. I didn’t expect to find out that the baby was a “Fernando”. The doctor said, “Fernando means hyper-masculinity or hypermasculinity, and “Fernando syndrome” is a sex chromosome abnormality syndrome, also known as “XYY syndrome” or “tall man syndrome”. It is also called “XYY syndrome” or “tall man syndrome”. The disease was first discovered and reported by foreign scholars in 1961, and it was suggested that patients with this disease are aggressive, have antisocial behavior, and often go to jail for indiscriminate violence and breaking the law. The symptoms of hyperandrogenic syndrome are not obvious in childhood, and the male secondary sexual characteristics are normal in adulthood, but the stature can be up to 1.8 meters or more, the length of the trunk and legs are long, the muscles are not strong, the movements are uncoordinated, the face is asymmetrical, the jaw is prominent, the ears are long, the bones have deformities especially the radius and ulna can be bony joint, and often suffer from pustular acne. Their external genital development is mostly normal, and although testicular function is diminished, some have normal sperm production and others are mildly impaired, so they can have normal or abnormal offspring, or no offspring. The level of male hormones in the blood is normal or slightly high. These people have below average intelligence, unstable personality, lack of self-control, poor emotional control, and vulnerability to fraud; on the other hand, they have a violent and aggressive temper, are aggressive, have antisocial behavior, and are prone to crime, including crime due to sexual misconduct. Chromosomal examinations of male offenders in the United Kingdom and the United States have found that the rate of XYY syndrome in institutions is 4 to 20 per 1,000, which is 4 to 20 times higher than the normal population. There is usually no special treatment for “Fernando syndrome”. After learning of these conditions, Mr. Wu chose to give up the fetus. So, why did the fetus have an extra Y chromosome when Mr. and Mrs. Wu both have normal chromosomes? This is mainly due to the fact that the sperm involved in fertilization contains 2 Y chromosomes. Normally, male cells contain 46 chromosomes, of which the sex chromosome is XY. Generally, both sperm and egg undergo two meiotic divisions before maturation, and eventually become haploid, containing only half of the 23 chromosomes, so that the sperm and egg can revert to 46 in the future after union. In some special cases, during the second meiosis, if the Y chromosome does not separate, one sperm has no sex chromosomes and the other has 2 Y chromosomes. If this sperm containing 24 and YY is combined with an egg containing 23 and X, the resulting fertilized egg will have a karyotype of 47 and XYY, and the resulting individual will develop into “Fernando syndrome”. What are the specific factors that cause the Y chromosome to be undifferentiated? This is not yet well understood, but studies have definitely shown that smoking increases the number of sperm with 2 Y chromosomes, doubling the incidence of boys with Fernando syndrome in their offspring. Mr. and Mrs. Wu have to take medication and injections, but there is no way to know what specific medication is used, and it is difficult to tell if it is related to this.