Han, who is 1.75 meters tall and has fatty tissue in her chest, had undergone puberty but had not started menstruation. Doctors at Tam Anh General Hospital, Ho Chi Minh City, noted her external genitalia were smaller than average. Advanced tests revealed Han possessed a 46,XY chromosome set, confirming her genetic sex as male. A pelvic MRI showed two streak gonads and fallopian tubes, but no ovaries, and an underdeveloped uterus.

Master of Science, Doctor Nguyen Thi Thanh Tam from the Obstetrics and Gynecology Center, diagnosed Han with Swyer syndrome. This congenital disorder of sex development affects approximately 1/80,000 live births. Swyer first described the syndrome in 1955 in two phenotypically female individuals who carried a 46,XY chromosome set. Individuals with Swyer syndrome have male chromosomes but appear female. However, their gonads do not develop into functional testes; instead, they remain as streak gonads, producing almost no sex hormones.

Disorders of sex development are categorized into three main groups based on chromosome type: 46,XX; 46,XY; and sex chromosome abnormalities. In individuals with 46,XY chromosomes, abnormalities can occur during gonad formation from the embryonic stage.

According to Doctor Tam, individuals with Swyer syndrome have gonads that do not develop into functional testes. Consequently, they do not produce testosterone or Mullerian inhibiting hormone (AMH) like normal testes would. This allows structures belonging to the Mullerian duct system, such as the uterus and fallopian tubes, to develop to varying degrees. Swyer syndrome is often detected when children reach puberty, as they do not exhibit full pubertal signs and do not experience menstruation.

Doctors performed laparoscopic surgery to remove both streak gonads and the entire uterine structure for Han, mitigating the risk of tumor development. Histopathology results confirmed Han had fibrotic testicular tissue with atrophied seminiferous tubules, incapable of sperm production. Her uterus was underdeveloped due to prolonged estrogen deficiency, rendering it unable to perform reproductive functions.

Doctor Thanh Tam (right) and her surgical team operate to remove Han's gonads. Photo: Tam Anh General Hospital

Han, therefore, has a female appearance but carries male chromosomes. She can choose to continue living as female or use male hormones to transition to male. However, Han and her family are not rushing to decide on her gender identity and will wait until she turns 18 to make a decision.

"If she chooses to live as female, due to her malformed reproductive organs, she has an underdeveloped uterus and ovaries that do not produce oocytes. In the future, if she wishes to have children, she would only be able to use donor eggs and a surrogate mother," Doctor Tam explained.

According to the World Health Organization (WHO), girls typically begin menstruating around 13 years old, depending on their physical condition. In Vietnam, this period usually ranges from 10-15 years old. Delayed or incomplete puberty can result from chromosomal disorders, reproductive organ abnormalities, ovarian insufficiency, hypothalamic-pituitary endocrine disorders, malnutrition or excessive weight loss, or chronic illnesses. Therefore, Doctor Tam advises that girls who have not started menstruating by age 15 should seek medical examination to detect any abnormalities and intervene promptly.

Tue Diem

* The character's name has been changed.