A Portuguese man had breasts, a micropenis and had a high-pitched voice because his testicles disappeared in the womb.
The unnamed patient was only diagnosed with "vanishing testis syndrome" at 42 - despite lacking testicles, which produce testosterone, his entire life.
Testosterone injections were administered to make up for his lack of the male sex hormone and helped develop a deeper voice, smaller breasts and even facial hair, according to the Daily Mail.
Doctors remain baffled as to exactly what happened to him as a child because he was separated from his parents as an infant.
However, they believe his testicles may have become twisted, which cut off their blood supply and caused them to waste away in the womb.
The bizarre tale was published by doctors in Lisbon in the British Medical Journal Case Reports.
The man, originally from the African country, Angola, went to Hospital de Egas Moniz complaining of the physical female features he had suffered with his entire life.
Doctors found he had "intersexuality" - when a person is born with hormones and genitals that "do not fit the typical definitions for male or female bodies".
Although he had a male face, his physique was womanly, with breasts, broad hips and shapely thighs, Dr Francisco Sousa Santos and colleagues revealed.
As well as having a micropenis, the man's testicles were also missing, which initially led medics to believe they never descended from his abdomen.
Although he admitted to being somewhat attracted to women in the past, he had never had sex.
A hormone test also revealed he was producing insufficient amounts of testosterone - which is produced by the testicles.
The medics then performed an ultrasound scan, which suggested his testicles were not lying undescended in his abdomen.
The patient decided against surgery to confirm this, but was diagnosed with bilateral anorchia, or VTS, on the back of his hormone test and ultrasound.
Vanishing testis syndrome is usually diagnosed at birth, which allows patients to have testosterone replacement therapy at a young age.
The man is just one of two known cases to be discovered during adulthood. Due to the condition's rarity, there are no guidelines on how best to treat it.
To combat his female features, doctors decided to inject 250mg of testosterone into the man's muscles every three weeks.
Within the first few months, he claimed to have a boosted libido, facial hair, a deeper voice, smaller breasts and more energy.
Doctors claim this case highlights how medics should be aware of hypogonadism - the reduction or absence of hormones produced by testes and ovaries - even in adults.